Picture Above - May 2018 Jo's grafting plum tree near Spruce Grove, Alberta
Newsletters and Shared Educational Material
Hello everyone. Below you will find postings of our Newsletters as well as educational materials that other fruit members want to share with the group. The shared information should be about your personal experiences in regards to growing fruits, berries, and nuts in our Canadian Prairie conditions. We welcome your trials, successes and learned lessons in these areas. Pictures are encouraged. We would like to share what works, what we are experimenting on and what failed. This page will be updated on a more regular basis as new material is shared.
DBG Fruit Growers’ Bulletin 1-20 added Jan. 29, 2020
Dehorning By Thean Pheh
Dehorning? No, I have not lose my marbles yet. This dehorning has nothing to do with animals. Yes, it has to do with apples and pears particularly those spur bearing types. In spring a mixed bud breaks and sends forth a few leaves before terminating with a cluster of flowers. These leaves are called spur leaves. At the axil of each spur leaf is a bud. As the little apple is growing; usually around the end of May in the Edmonton area; one of these will develop and grow, producing a couple of leaves before terminating into either a vegetative or mixed bud. This results in the formation of a spur to keep the fruiting point alive for many years. However in many spur varieties more than one bud develop in some years. Hence instead of a single bud spur we now a multiple bud spur. One may give rise to two, and two to three or four, and so on. This phenomenon gives rise to what is called a complicated spur. For lack of better terminology let us name these as secondary spurs.
Normally there are anywhere from 3 to 7 flowers to a mixed bud. Hence, if there are 4 secondary spurs in a complicated spur there will be 12 to 28 flowers in that complicated spur. No matter how many secondary spurs there are on a complicated spur there should only be an apple on each complicated spur. With many more fruits to thin out fruit thinning on complicated spurs is very laborious and time consuming. Commercial growers used to prune complicated spur to a single bud. This pruning is called dehorning. Dehorning will reduce labor required for fruit thinning. Fruits also get better exposure to the sun thereby enabling them to develop deeper skin color.
Although dehorning requires less labor than fruit thinning it is nonetheless also time consuming and labor intensive. With higher labor cost and shortages it is no longer economically viable for commercial producers to dehorn. Complicated spurs may also have gone down the path of the dodo in modern high density orchards where laterals are treated as replaceable fruiting scaffolds. But for us home gardeners, where standard or semi-standard trees are still the norm and tree shapes are important part of the landscape, complicated spurs are here to stay. Since time and cost are not determining factors we must weigh our options between dehorning and timely heavy flower and fruit thinning.
Dehorning is best done in spring as part of annual pruning. Let’s take an example of a complicated spur with four secondary spurs. I try to keep the shortest and closest spur/bud to the point of origin. Instead of sharing nutrients with three other buds, all the nutrients are now channelled to the reminding one. Hence dehorning increases the vigor of the retained spur. This may spur development of more than a bud and cause the return of complicated spur. Hence dehorning of spur may be an annual affair.
Instead of dehorning some growers prefer to thin all apples to retain only one on each complicated spur. After pollination the developing apples depend on food reserves stored in the vicinity of the spur to grow. Since this supply is rather small, regardless of how many secondary spurs a complicated spur has it must be treated as a simple spur. This is my modus operandi. As soon as the flowers have elongated long enough for easy removal, I pick the strongest secondary spur and remove all flowers on the rest in that complicated spurs. With this the tree does not have to expend unnecessary energy to develop all the flowers. Energy thus saved goes directly to initiate and develop mixed buds for next year. My next step is to remove all except three flowers on the selected secondary spur. As soon as the retained flowers have bloom I start to thin out the apples, either end of May or first week of June in the Edmonton area. With this modus operandi I get bigger fruits and eliminate biennial fruiting or the well-known heavy and light fruiting cycle. There is a downside to this practice. Apples in complicated spurs are surrounded by too many leaves. This results in less colorful fruits.
Normally there are anywhere from 3 to 7 flowers to a mixed bud. Hence, if there are 4 secondary spurs in a complicated spur there will be 12 to 28 flowers in that complicated spur. No matter how many secondary spurs there are on a complicated spur there should only be an apple on each complicated spur. With many more fruits to thin out fruit thinning on complicated spurs is very laborious and time consuming. Commercial growers used to prune complicated spur to a single bud. This pruning is called dehorning. Dehorning will reduce labor required for fruit thinning. Fruits also get better exposure to the sun thereby enabling them to develop deeper skin color.
Although dehorning requires less labor than fruit thinning it is nonetheless also time consuming and labor intensive. With higher labor cost and shortages it is no longer economically viable for commercial producers to dehorn. Complicated spurs may also have gone down the path of the dodo in modern high density orchards where laterals are treated as replaceable fruiting scaffolds. But for us home gardeners, where standard or semi-standard trees are still the norm and tree shapes are important part of the landscape, complicated spurs are here to stay. Since time and cost are not determining factors we must weigh our options between dehorning and timely heavy flower and fruit thinning.
Dehorning is best done in spring as part of annual pruning. Let’s take an example of a complicated spur with four secondary spurs. I try to keep the shortest and closest spur/bud to the point of origin. Instead of sharing nutrients with three other buds, all the nutrients are now channelled to the reminding one. Hence dehorning increases the vigor of the retained spur. This may spur development of more than a bud and cause the return of complicated spur. Hence dehorning of spur may be an annual affair.
Instead of dehorning some growers prefer to thin all apples to retain only one on each complicated spur. After pollination the developing apples depend on food reserves stored in the vicinity of the spur to grow. Since this supply is rather small, regardless of how many secondary spurs a complicated spur has it must be treated as a simple spur. This is my modus operandi. As soon as the flowers have elongated long enough for easy removal, I pick the strongest secondary spur and remove all flowers on the rest in that complicated spurs. With this the tree does not have to expend unnecessary energy to develop all the flowers. Energy thus saved goes directly to initiate and develop mixed buds for next year. My next step is to remove all except three flowers on the selected secondary spur. As soon as the retained flowers have bloom I start to thin out the apples, either end of May or first week of June in the Edmonton area. With this modus operandi I get bigger fruits and eliminate biennial fruiting or the well-known heavy and light fruiting cycle. There is a downside to this practice. Apples in complicated spurs are surrounded by too many leaves. This results in less colorful fruits.
DBG Fruit Growers’ Bulletin 5-19 added Nov. 12, 2019
Bernie and his pal Justin have just made 4 new short YouTube videos. All are short 3 or 4 minutes each on topics of interest to cold weather fruit growers. Just click on the link below to see these recent videos and, and also check out some of his other videos on grafting (on the same Veritas 555 777 channel).
Amazing Scionwood Storage Method. You can also read the article on this topic below ( Oct. 23, 2019)
https://youtu.be/KRSIj63iNhM
Overwintering Fig Trees in Canada
https://youtu.be/l6nzG6RicoI
Siberian Peach Tree Method - Grow Peaches in minus 40C
https://youtu.be/gvDu1EviOnU
Tree Tenting Method Add +10 to +15C in the winter
https://youtu.be/m9qWjLL6bXg
Gabe has provided this link below, to all those of you that just love more information on Fruit Growing.
https://www.pdfdrive.com/temperate-zone-pomology-physiology-and-culture-e189191108.html
...lots of other great nonfiction books available for free download as well.
Amazing Scionwood Storage Method. You can also read the article on this topic below ( Oct. 23, 2019)
https://youtu.be/KRSIj63iNhM
Overwintering Fig Trees in Canada
https://youtu.be/l6nzG6RicoI
Siberian Peach Tree Method - Grow Peaches in minus 40C
https://youtu.be/gvDu1EviOnU
Tree Tenting Method Add +10 to +15C in the winter
https://youtu.be/m9qWjLL6bXg
Gabe has provided this link below, to all those of you that just love more information on Fruit Growing.
https://www.pdfdrive.com/temperate-zone-pomology-physiology-and-culture-e189191108.html
...lots of other great nonfiction books available for free download as well.
DBG Fruit Growers’ Bulletin 4-19 added Oct. 23, 2019
New Excellent Way To Store Fruit Tree Scions! By Bernie Nikolai
This has worked really well for me in the last two years testing. No matter how cold a test winter we get, the scions are in good shape for grafting in the spring. This method is ESPECIALLY good for storing scions of marginal varieties that can easily be damaged in our challenging winters due to cold temperatures.
Basically, you bury a 5 gallon plastic Home Depot pail or similar to near the rim in your garden in the shade on the north side of a fence or building. So the bottom of the pail is about 15 inches below the surface of the ground.
You cut the scions really early, not in March, but in NOVEMBER no later than the first day after the minimum temperature at night hits -15C (roughly mid November on average, but it can be earlier or later). You store them in zip lock bags with a tiny piece of damp paper towel, very similar to what you would do in April in your fridge with cut scions.
You place the scions into the bucket, snap on the plastic lid (important so spring melted snow won't melt into the bucket), and cover with a big bag of raked leaves. When it snows cover the bag of leaves with snow as well. You can check/add to/remove the scions at any time in the winter by removing the bag of leaves and taking off the lid of the bucket.
No matter how cold it gets in winter, the minimum temperature I have ever recorded is -5C all winter inside the bucket. The temperature is amazingly consistent, and only varies perhaps a half degree C in a month. Tests at Washington State University show the perfect temperature to store scions is slightly below freezing, around -1C to -5C. A freezer, even a fridge freezer, is often too cold, but this ground bucket storage method is perfect in terms of temperature! A fridge is way too warm at +5C for long term storage longer than a month or so, especially with cherries and plums.
This is the only real way to store sweet cherry and tender plum scions, as they are usually damaged by cold if you cut the scions in late March, the normal time. But you can store any variety of apple, pear, plum, cherry, etc. with this method. If a test winter kills your tree/grafts, you still have lots of good viable scions to regraft in spring from your bucket! Once the temperature in the bucket reaches +4C about mid April I move the scion bags to my fridge, and they are all grafted within about 2 weeks after that.
This method has been used for decades with excellent results in a similar climate in Russia, and I can vouch for the fact any scions are in excellent shape come grafting time in late April, May.
First photo is my buried bucket with the plastic lid snapped on, plus another identical bucket beside it to show the size. Second and third photos are looking into the bucket showing a max/min thermometer inside.
Basically, you bury a 5 gallon plastic Home Depot pail or similar to near the rim in your garden in the shade on the north side of a fence or building. So the bottom of the pail is about 15 inches below the surface of the ground.
You cut the scions really early, not in March, but in NOVEMBER no later than the first day after the minimum temperature at night hits -15C (roughly mid November on average, but it can be earlier or later). You store them in zip lock bags with a tiny piece of damp paper towel, very similar to what you would do in April in your fridge with cut scions.
You place the scions into the bucket, snap on the plastic lid (important so spring melted snow won't melt into the bucket), and cover with a big bag of raked leaves. When it snows cover the bag of leaves with snow as well. You can check/add to/remove the scions at any time in the winter by removing the bag of leaves and taking off the lid of the bucket.
No matter how cold it gets in winter, the minimum temperature I have ever recorded is -5C all winter inside the bucket. The temperature is amazingly consistent, and only varies perhaps a half degree C in a month. Tests at Washington State University show the perfect temperature to store scions is slightly below freezing, around -1C to -5C. A freezer, even a fridge freezer, is often too cold, but this ground bucket storage method is perfect in terms of temperature! A fridge is way too warm at +5C for long term storage longer than a month or so, especially with cherries and plums.
This is the only real way to store sweet cherry and tender plum scions, as they are usually damaged by cold if you cut the scions in late March, the normal time. But you can store any variety of apple, pear, plum, cherry, etc. with this method. If a test winter kills your tree/grafts, you still have lots of good viable scions to regraft in spring from your bucket! Once the temperature in the bucket reaches +4C about mid April I move the scion bags to my fridge, and they are all grafted within about 2 weeks after that.
This method has been used for decades with excellent results in a similar climate in Russia, and I can vouch for the fact any scions are in excellent shape come grafting time in late April, May.
First photo is my buried bucket with the plastic lid snapped on, plus another identical bucket beside it to show the size. Second and third photos are looking into the bucket showing a max/min thermometer inside.
DBG Fruit Growers’ Bulletin 3-19 added July 5, 2019
I Do It My Way By Thean Pheh and Gabe Botar
(Collecting scionwood in February or October, storing & chip budding in July)
Thean : Most of us harvest our scionwood in March or April and then keep them in the refrigerators crisper until it’s time to graft in May to June. Based on plant physiology, I think this is a bad practice. Most plants would have already got their cold chill requirement by March. That means they could have moved because there are always days in March and April when the ambient temperature is well above the freezing point. Water that the trees had downloaded into the intercellular spaces in preparation for winter could have moved back into the cells. Refreezing of water within cells is bad or fatal for plants. Hence there is the possibility of us harvesting badly damaged scionwood. There were occasions when scionwood I harvested in February were without any damage, the sapwood were perfectly alive and white. Scionwood harvested from the same donor trees in April were either dead or the sapwood were dark brown ie dead; only the buds and cambium were alive. Success from grafting with such scionwood can be extremely poor. The temperature in most crisper is around +2oC to +4oC. Even when there is no damage, scionwood kept at this constant temperature will start to move. Hence many of us are left with dehydrated scionwood or scionwood with emerging buds when it’s time for us to graft.
To circumvent this problem I harvest my scionwood while the woods are still fully frozen, normally in Mid-February in metropolis Edmonton, well before there is a day where the temperature is above freezing. The harvested scionwood is immediately wrapped with wet paper towels and placed in a plastic freezer bag and thrown into the freezer. (Remember to label if there are more than one cultivar and try to squeeze out as much air as possible from the bag before sealing.) Not all plastic are created equal. Only freezer bag will do. Materials stored in regular plastic will suffer from freezer burns. To be sure sometimes I double freezer bagged. The scionwood is never allowed to thaw out from the trees to the freezer. One day before grafting I remove the scionwwod from the freezer and place the bag in the refrigerator to thaw out gradually.
Gabe: I would mention that I have always tried to collect scionwood in February, mainly for the reasons you have listed. Did get positive feedback on the quality of my scionwood ! The other thing I now do (since our fridge is now a self-defrosting one) is keeping the scionwood in its plastic bag inside a bubble-wrap envelope in the crisper for the few weeks until I graft, after mid-May. Not using the bubble-wrap used to result in damaged scions because of the alternating temperatures inside the self-defrosting fridge. Back at F64, I always kept the scionwood in an old-fashioned antique fridge that kept temperatures steady, and could keep scions in good shape all the way into July. (In fact, I did graft some apples in July long ago, and there was enough time for the new growth to harden off before winter.)
Thean: Yes, it can be troublesome walking through deep snow in freezing temperature to get to the donor plants. But, it’s good exercise for burning off the extra weight gained from eating too much over the end of the year and New Year festivities. This method may not be practical for most of us especially if we have to depend on getting our materials from the annual scionwood exchange in DBG or if scionwood had to be shipped in from another area.
Another method I used to practice but have abandoned for more than two decades is to harvest the scionwood in fall after all the leaves had dropped off, around October. The fence on the south side of my yard is solid 8x4 feet plywood to about 5 feet high. About three feet of soil at the north side never
get the spring sun. I buried the harvested scionwood 6 to 8 inches before covering them to about 4 inches with dried leaves collected during fall cleanup. When I was shovelling snow I threw the snow over the mulch. That will be last place in my yard to be snow free in spring. After the soil had thawed out and dry enough, normally early May, before I dug and recovered the scionwood. The wood was then stored in plastic bag in the crisper until required. The reasons I dropped this practice was too much time and labor were required. Also, very often buds on the wood had sprouted by the time I recovered them. Thirdly there were years when the soil was already frozen by October.
Gabe: For some reason, I never even tried fall scion collection, except when I was experimenting with bench-grafted interstem callusing...but that is another story again...
Thean: Commercial nursery operators produce millions of grafted trees each year. Interestingly none of them graft; every plant was budded. Why then are we not following the footsteps of the professionals? Since budding is not only easier and faster but success is also higher I do most of my propagation by budding. Alberta Agriculture recommends doing it in August to early September. I prefer to do it starting from the third week of July. I’m still in the old school and expect the first killing frost within the first week of September. (Maybe with global warming frost will come later!) Since my rule of thumb is to stop budding three weeks before the expected first frost I stop budding by mid-August. There are many methods of budding practiced around the world. The three I used are “T”, chip and a method that I came up with by combining the chip and patch methods. The disadvantage with budding in summer is the budwood is actively growing and extra precautions must be taken to prevent dehydration. Budwood is also best used within a week from harvesting.
Gabe: One disadvantage vis-a-vis grafting is the one-year delay to first flower. For hobbyists, the advantages of grafting are more obvious than for commercial orchards.
Footnote: Wood used for grafting is called scionwood while that used for budding is called budwood.
DBG Fruit Growers’ Bulletin 2-19 added May 24, 2019
Gummosis, anyone ? By Gabe Botar added May 24, 2019
If you have one or more stone fruits (apricot, cherry, plum etc.) chances are that you have seen brownish-coloured resinous sap oozing from the bark of at least some of your trees. That glob of sticky sap is referred to as "gummosis" and it usually means that you need to take action if you want your tree to thrive.
The first (and usually obvious) explanation for gummosis is mechanical wounding of the bark. (Yes, woodpeckers and insects may be among the culprits.) In and of itself this may be only a minor problem, but the glob of sap will attract microbes and some of those will probably be pathogenic. Also, if you are grafting and experience gummosis at the grafting site, your graft is probably at risk for failure. (Working quickly and precisely usually alleviates this risk.)Whether the gummosis involves only mechanical injury or pathogens as well, you will need to correct the problem.
Another frequent culprit is "sunscald", sometimes called "southwest injury". During the day in late winter, solar radiation will heat up the dark-coloured bark enough to let liquid water hydrate stem tissues ; sap will start flowing upwards through the xylem. However, at that time of year overnight temperatures usually drop below the freezing point of the sap, even if that is less than zero Celsius because of the dissolved solutes in the sap. When hydrated cells freeze, their water turns to ice crystals. Now we know that ice is less dense than liquid water (that is why ice cubes float), so the crystals now occupy a larger volume than did the liquid water earlier. Result : the cell membrane breaks and the cell contents ooze into the spaces between the relatively resilient cell walls (which can also become deformed). Sap droplets appear on the surface of the bark.
Have you ever heard of Pseudomonas syringae pv. syringae van Hall ? (I'll call it PS here for the sake of brevity.) Pseudomonas is a genus of almost 200 types of bacteria that live in a wide variety of habitats : they can cause hospital infections, food spoilage, sick mushroom farms etc. The "syringae"in the name of the bacterium in question gives away its significance, in that it was first isolated in lilacs. PS will infect a wide range of plant species, including the stone fruits in the genus Prunus. Now PS produces ice-nucleating proteins, which cause sap to freeze at higher temperatures than would normally be the case : healthy sap usually will not freeze at -2C because of its solutes, but PS will promote some cell freezing at that temperature. See how PS can make gummosis even more likely ?
As if a mechanical trauma or primary infection by PS were not enough, various species of pathogenic fungi often enter the stem tissues to cause secondary infections. In warmer climates where sunscald is not much of a problem, fungal gummosis is ! The "cankers" (areas of usually sunken dead tissue on the bark) will spread if not eradicated, thus ultimately killing the tree if the main trunk is compromised.
What to do ? Well, the first step is to remove the globs since they may be teeming with pathogenic inocula. A paper towel soaked with 50-70% alcohol will do.
Next, if there are cankers, they will need to be "shaved" down to healthy wood, provided the cankers are not too deep (in which case the affected branch needs to be pruned off carefully, making sure not to spread the inoculum.) The shaved area is then swabbed with alcohol or given a short sterilizing blast with a propane torch (not both !) and finally it is spray-painted or brushed with anti-rust paint.
Finally, the whole trunk should be kept painted with white latex paint. This procedure is useful for two reasons. The first is that white reflects sunlight, so the bark will not heat up as easily in late winter -- ice crystals are less likely to form, so cell damage is minimized. Secondly, any gummosis will be more easily spotted against a white background. Some people also add fungicides to the latex paint (for obvious reasons) and maybe even a bitter substance such as denatonium benzoate (Bitrex) to deter gnawing mammals. If you have ever used Skoot as a deterrent, you may have noticed that its bitter prime ingredient Thiram is also a potent fungicide !
In summary, gummosis can be a serious problem in Prunus trees. Where possible, prune out affected branches. (Bag, burn or bury the prunings -- do not leave them lying around !) Otherwise, clean and sterilize cankers to destroy as much inoculum as possible. Paint trees with white latex to prevent sunscald, and repeat as needed.
The first (and usually obvious) explanation for gummosis is mechanical wounding of the bark. (Yes, woodpeckers and insects may be among the culprits.) In and of itself this may be only a minor problem, but the glob of sap will attract microbes and some of those will probably be pathogenic. Also, if you are grafting and experience gummosis at the grafting site, your graft is probably at risk for failure. (Working quickly and precisely usually alleviates this risk.)Whether the gummosis involves only mechanical injury or pathogens as well, you will need to correct the problem.
Another frequent culprit is "sunscald", sometimes called "southwest injury". During the day in late winter, solar radiation will heat up the dark-coloured bark enough to let liquid water hydrate stem tissues ; sap will start flowing upwards through the xylem. However, at that time of year overnight temperatures usually drop below the freezing point of the sap, even if that is less than zero Celsius because of the dissolved solutes in the sap. When hydrated cells freeze, their water turns to ice crystals. Now we know that ice is less dense than liquid water (that is why ice cubes float), so the crystals now occupy a larger volume than did the liquid water earlier. Result : the cell membrane breaks and the cell contents ooze into the spaces between the relatively resilient cell walls (which can also become deformed). Sap droplets appear on the surface of the bark.
Have you ever heard of Pseudomonas syringae pv. syringae van Hall ? (I'll call it PS here for the sake of brevity.) Pseudomonas is a genus of almost 200 types of bacteria that live in a wide variety of habitats : they can cause hospital infections, food spoilage, sick mushroom farms etc. The "syringae"in the name of the bacterium in question gives away its significance, in that it was first isolated in lilacs. PS will infect a wide range of plant species, including the stone fruits in the genus Prunus. Now PS produces ice-nucleating proteins, which cause sap to freeze at higher temperatures than would normally be the case : healthy sap usually will not freeze at -2C because of its solutes, but PS will promote some cell freezing at that temperature. See how PS can make gummosis even more likely ?
As if a mechanical trauma or primary infection by PS were not enough, various species of pathogenic fungi often enter the stem tissues to cause secondary infections. In warmer climates where sunscald is not much of a problem, fungal gummosis is ! The "cankers" (areas of usually sunken dead tissue on the bark) will spread if not eradicated, thus ultimately killing the tree if the main trunk is compromised.
What to do ? Well, the first step is to remove the globs since they may be teeming with pathogenic inocula. A paper towel soaked with 50-70% alcohol will do.
Next, if there are cankers, they will need to be "shaved" down to healthy wood, provided the cankers are not too deep (in which case the affected branch needs to be pruned off carefully, making sure not to spread the inoculum.) The shaved area is then swabbed with alcohol or given a short sterilizing blast with a propane torch (not both !) and finally it is spray-painted or brushed with anti-rust paint.
Finally, the whole trunk should be kept painted with white latex paint. This procedure is useful for two reasons. The first is that white reflects sunlight, so the bark will not heat up as easily in late winter -- ice crystals are less likely to form, so cell damage is minimized. Secondly, any gummosis will be more easily spotted against a white background. Some people also add fungicides to the latex paint (for obvious reasons) and maybe even a bitter substance such as denatonium benzoate (Bitrex) to deter gnawing mammals. If you have ever used Skoot as a deterrent, you may have noticed that its bitter prime ingredient Thiram is also a potent fungicide !
In summary, gummosis can be a serious problem in Prunus trees. Where possible, prune out affected branches. (Bag, burn or bury the prunings -- do not leave them lying around !) Otherwise, clean and sterilize cankers to destroy as much inoculum as possible. Paint trees with white latex to prevent sunscald, and repeat as needed.
DBG Fruit Growers’ Bulletin 1-19 added Feb. 7, 2019
Summary of info gathered in Grafting Laboratory, Pl.Sc. 335.
Grafting Fruit Compatibility-Hints By Gabe Botar added Feb. 7, 2019
1. Know your plant material ! This will guide you in choosing compatible stocks and scions, and give you greater control over the final size, shape and makeup of your grafted plant .
2. Safety above all !!! Use appropriate tools. Your grafting/budding knife must be razor-sharp, rigid and unbreakable. When tying/sealing the graft area, be aware that in order to prevent girdling you may eventually need to cut the cloth tape, raffia, etc. used to hold the stock and scion together. (Softer materials such as rubber budding strips, parafilm, and masking tape will usually degrade and fall off on their own, without needing to be cut. Vinyl tape and rubber/silicone tape will probably need monitoring/cutting to prevent girdling.)
3. Evergreen tropical plants and greenhouse ornamentals can usually be grafted in any season, but spring is usually best since day length is increasing then. Monocots cannot be grafted.
4. In the Edmonton area, observe the following Rules of Thumb for fruit trees (apples, pears, plums, cherries) :
a. Collect dormant scionwood/budsticks in late February/early March ; store with a moist (not wet !) paper towel in a sealed plastic bag in the refrigerator, at 2-4C. ((Scions may last for months if kept this way at 2C…and for a week or so if kept at 10C.)
b. Graft or bud after May 1. The best time is about mid-May. At this point the sap is rising in the stock but the scions should still be dormant. If you can keep a scion dormant, it may be grafted successfully onto a suitable rootstock as late as July, and still make growth and harden off in time for the coming winter. All the grafts will work this way, as will chip & Jones buds.
c. The first week in August is usually the “window” for doing T-buds, because the stock bark is “slipping” then. Whereas the scionwood/ budsticks used around May 1 and later have no foliage, T-buds will have leaves at the nodes. (Remove the leaf blades but keep the petioles, which are good little handles ; after the budding procedure, the petioles should fall off after 10 days or so.) On the budstick, avoid basal and terminal buds, choosing the plump and mature medial buds of the current season’s growth. Jones and chip buds do not need to have the stock bark "slipping" and have a wider latitude for budding time.
5. Be clear about the difference between TOPWORKING and FRAMEWORKING, and the advantages of each.
6. Some Grafting Compatibility Hints Below:
a. Graft Apples : A species is usually graft-compatible on its own seedlings ; thus, an apple will usually graft successfully onto an apple, etc. In our climate, just about any Malus scion will graft onto the same or another Malus cultivar or species. Crabapples and large-fruited apples can be grafted onto each other, but be aware of what can happen when stocks and scions with very different growth rates and growth habits are combined.
b. Graft plums and cherry-plum hybrids onto most plums, sandcherry, or nanking cherry.
c. Graft hardy apricots onto sandcherry, but not onto nanking cherry or plum (some salicinas excepted), unless you want to hold the scion for only a couple of seasons or less before final grafting onto a sandcherry. Apricots on sandcherry need to be staked. If you use sandcherry as an interstem, apricots will usually do well on plums and nanking cherries.
d. Graft pears onto saskatoons and cotoneasters and some hawthorns (especially Japanese) and mountain ash. Note the need to keep some of the original foliage below the graft on saskatoons and cotoneasters. Compatible mountain ash rootstocks do not have this requirement and usually do not need staking. If using seedlings for pear rootstocks, use seeds from hybrid hardy pears rather than seeds from pure Ussurian pear lines.
e. Graft saskatoons onto cotoneaster (usually successful) or compatible mountain ash. If the compatibility with the mountain ash is unknown, try a cotoneaster interstem.
f. Graft sour cherry onto mongolian cherry or pincherry (or hardy sweet cherry in relatively warm microclimates). Seedlings of the sour cherry 'Evans' are usually compatible stocks for sweet and sour
cherries here but often short-lived. Alternatively, sweet and sour cherries can usually be grafted onto Amur cherry or Amur cherry interstems on mayday. The hardiest sweet cherries in our area usually graft well onto 'Evans' sour cherry. The true (sweet and sour) cherries are usually not compatible on sandcherry or nanking cherry, which are more closely related to plums.
g. Graft chokecherry onto amur cherry, or mayday (usually, but not always; consider using an Amur cherry interstem on maydays). (Chokecherries are not compatible with the true cherries in f. above).
h. Graft red and white currants and gooseberries onto Ribes aureum or its close relatives (usually successful) ; the resulting plants are taller, more productive, and easier to harvest).
i. Common (French) lilacs (Syringa vulgaris) often sucker badly. They can be grafted successfully onto non-suckering late lilacs (Syringa villosa) only if an interstem of dwarf Korean lilac (Syringa meyeri) is used
2. Safety above all !!! Use appropriate tools. Your grafting/budding knife must be razor-sharp, rigid and unbreakable. When tying/sealing the graft area, be aware that in order to prevent girdling you may eventually need to cut the cloth tape, raffia, etc. used to hold the stock and scion together. (Softer materials such as rubber budding strips, parafilm, and masking tape will usually degrade and fall off on their own, without needing to be cut. Vinyl tape and rubber/silicone tape will probably need monitoring/cutting to prevent girdling.)
3. Evergreen tropical plants and greenhouse ornamentals can usually be grafted in any season, but spring is usually best since day length is increasing then. Monocots cannot be grafted.
4. In the Edmonton area, observe the following Rules of Thumb for fruit trees (apples, pears, plums, cherries) :
a. Collect dormant scionwood/budsticks in late February/early March ; store with a moist (not wet !) paper towel in a sealed plastic bag in the refrigerator, at 2-4C. ((Scions may last for months if kept this way at 2C…and for a week or so if kept at 10C.)
b. Graft or bud after May 1. The best time is about mid-May. At this point the sap is rising in the stock but the scions should still be dormant. If you can keep a scion dormant, it may be grafted successfully onto a suitable rootstock as late as July, and still make growth and harden off in time for the coming winter. All the grafts will work this way, as will chip & Jones buds.
c. The first week in August is usually the “window” for doing T-buds, because the stock bark is “slipping” then. Whereas the scionwood/ budsticks used around May 1 and later have no foliage, T-buds will have leaves at the nodes. (Remove the leaf blades but keep the petioles, which are good little handles ; after the budding procedure, the petioles should fall off after 10 days or so.) On the budstick, avoid basal and terminal buds, choosing the plump and mature medial buds of the current season’s growth. Jones and chip buds do not need to have the stock bark "slipping" and have a wider latitude for budding time.
5. Be clear about the difference between TOPWORKING and FRAMEWORKING, and the advantages of each.
6. Some Grafting Compatibility Hints Below:
a. Graft Apples : A species is usually graft-compatible on its own seedlings ; thus, an apple will usually graft successfully onto an apple, etc. In our climate, just about any Malus scion will graft onto the same or another Malus cultivar or species. Crabapples and large-fruited apples can be grafted onto each other, but be aware of what can happen when stocks and scions with very different growth rates and growth habits are combined.
b. Graft plums and cherry-plum hybrids onto most plums, sandcherry, or nanking cherry.
c. Graft hardy apricots onto sandcherry, but not onto nanking cherry or plum (some salicinas excepted), unless you want to hold the scion for only a couple of seasons or less before final grafting onto a sandcherry. Apricots on sandcherry need to be staked. If you use sandcherry as an interstem, apricots will usually do well on plums and nanking cherries.
d. Graft pears onto saskatoons and cotoneasters and some hawthorns (especially Japanese) and mountain ash. Note the need to keep some of the original foliage below the graft on saskatoons and cotoneasters. Compatible mountain ash rootstocks do not have this requirement and usually do not need staking. If using seedlings for pear rootstocks, use seeds from hybrid hardy pears rather than seeds from pure Ussurian pear lines.
e. Graft saskatoons onto cotoneaster (usually successful) or compatible mountain ash. If the compatibility with the mountain ash is unknown, try a cotoneaster interstem.
f. Graft sour cherry onto mongolian cherry or pincherry (or hardy sweet cherry in relatively warm microclimates). Seedlings of the sour cherry 'Evans' are usually compatible stocks for sweet and sour
cherries here but often short-lived. Alternatively, sweet and sour cherries can usually be grafted onto Amur cherry or Amur cherry interstems on mayday. The hardiest sweet cherries in our area usually graft well onto 'Evans' sour cherry. The true (sweet and sour) cherries are usually not compatible on sandcherry or nanking cherry, which are more closely related to plums.
g. Graft chokecherry onto amur cherry, or mayday (usually, but not always; consider using an Amur cherry interstem on maydays). (Chokecherries are not compatible with the true cherries in f. above).
h. Graft red and white currants and gooseberries onto Ribes aureum or its close relatives (usually successful) ; the resulting plants are taller, more productive, and easier to harvest).
i. Common (French) lilacs (Syringa vulgaris) often sucker badly. They can be grafted successfully onto non-suckering late lilacs (Syringa villosa) only if an interstem of dwarf Korean lilac (Syringa meyeri) is used
DBG Fruit Growers’ Bulletin 2-18 added Sept. 26, 2018
My Blueberry Story By Thean Pheh added Sept. 26, 2018
Blueberries are native to many temperate countries around the world. Several species are native to North America. Among those native to Canada are the highbush, low sweet, ground hurt and velvet leaf. Only the velvet leaf, Vaccinium myrtilloides is native to Alberta. Lesser known is the black huckleberry, Vaccinium membranaceum, a very close relative that can be found in some parts of the Rocky Mountains.
Long before nutritionists touted blueberry as superfood it was highly valued by First Nation people and our forefathers. Many family outings used to be planned around the period when the native blueberries were ripening. Areas that produced heavily or high qualities berries were family’s top secrets.
With better transportation and storage facilities more and more berries are available in stores that resulted in less and less family outings nowadays. In the past demands for blueberry plants were very low to non-existence. However frequent airing and published articles on the health benefits of blueberry turned the table. More and more gardeners want to grow their own and this encourages every garden centres to carry some seedlings in spring.
Blueberries like all species in the Vacccinium Genus are very fussy and require very acidic soils to grow well. Most literature noted pH ranges from 4.5 to 6 as ideal. Although pines, Pinus spp. will tolerate neutral soil they grow best in slightly acidic soil. Over time they alter the soil reaction and lower the pH slightly. That’s why rookie blueberry foragers are told to look for pine forest to begin their hunt.
I envy some of our members who are on isolated pockets of acidic soil. When I started in the 80s, like every other gardener, I was told to amend my bed with liberal amount of peat moss before planting. I did that. A season of optimism soon turned sour when I inherited nothing but frustration and anguish. The pH of the black Chernozemic soil in Edmonton and immediate surrounding area is around 7.2 or higher. With high OM and clay it is very difficult to amend and maintain the adjusted pH for long: the upward moisture movement soon increases the pH within a couple of years. A couple of specialists suggested application of aluminium sulphate but I was hesitant because excess of aluminium leads to toxicity that can make growing any plants very, very difficult. Sulphur was also recommended but sulphur takes too many years to affect soil pH changes. Almost all blueberry plants sold in Alberta are hybrids between the low sweet x highbush blueberries - V. angustifolium x V. corymbosum. Although most literature listed them as hardy to Zone 3 results are very, very inconsistent and disappointing. The plants survived but suffered from severe winterkill(1). Since the initiated floral buds are on last year’s wood winterkill meant no flowers and berries. By the early 90s I gave up growing blueberries.
I was transferred to Brooks in 2002. The end of spring sales was too good to pass and I ended buying a Northblue and a Northline blueberry plants. The brown Chernozemic soil in my yard was not only alkaline but also slightly saline. Since I was already into bonsai or penjing I decided to grow the two plants in containers. The small volume of soil in container is so much easier to adjust and maintain. The other reason is providing extra winter protection is a breeze when plants are planted in containers. In fall before the snow flies I placed the pots on its side and cover the canes with fallen leaves collected from other trees. Snow added more insulation. By resisting the temptation to uncover the plants as soon as the snow had melted in spring, I have been harvesting blueberries since then (2).
Acidic soil restricts the availability of many nutrients. Blueberries overcome that by developing a symbiotic relationship with mycorrhizae, a soil dwelling fungus. As such do not wash off any soil that come with your purchased plants. If you dig from the wild, be sure to bring home some soil with your dug out plants. I mix my own potting soil using equal volume of play sand, peat moss and soil from my yard. How do I keep the pH low? I water with Ammonium sulphate in spring and fertigate with water soluble fertilizers formulated for roses or evergreens every 7 to 10 days from June to end of August. To avoid building up the salinity I use ¼ of the recommended rate. For daily watering I try not to use tap water since Edmonton’s supply is alkaline. I either use rainwater collected from the roof into barrels or I use ‘rice’ water. (I collect water used for washing rice before cooking or pasta water (without salt) and allow it to ferment for several days.) Instead of throwing away the water used for rinsing milk containers, I use it to water my blueberry or lingonberry plants (3).
I do not have honey bees in my yard and as such I do not know if honey bees are attracted to blueberry’s flowers. So far I noticed that the various bumblebees are the only native bees that work among my blueberries.
(1) I found even the local velvet leaf blueberry suffered winterkill unless it is under snow.
(2) In truth I pick very little; my grandchildren beat me to the berries every year.
(3) Milk not only helps to lower pH when it sours but also is beneficial to soil microbes.
Footnote
If you have success growing blueberries in other ways, please share your secrets. Other growers will appreciate your generosity. Last year I met a gardener who dug down to two feet and lined the bottom and sides with plastic. After punching a few holes at the bottom to allow excess water to drain out he filled it with purchased potting soil. With this method he needs not water his plants every day. For winter protection he erected a wall with chicken wire netting around his blueberry plants and filled it with leaves or straw.
There are other berries that are easily grown in Alberta. These berries not only have just as much or more antioxidants than blueberries they are also much less demanding. Saskatoon, black elderberry, black currant, Aronia and haskap are excellent examples. So if you do not want to go through the hassle of watering container grown blueberry every day, plant these alternatives instead.
Long before nutritionists touted blueberry as superfood it was highly valued by First Nation people and our forefathers. Many family outings used to be planned around the period when the native blueberries were ripening. Areas that produced heavily or high qualities berries were family’s top secrets.
With better transportation and storage facilities more and more berries are available in stores that resulted in less and less family outings nowadays. In the past demands for blueberry plants were very low to non-existence. However frequent airing and published articles on the health benefits of blueberry turned the table. More and more gardeners want to grow their own and this encourages every garden centres to carry some seedlings in spring.
Blueberries like all species in the Vacccinium Genus are very fussy and require very acidic soils to grow well. Most literature noted pH ranges from 4.5 to 6 as ideal. Although pines, Pinus spp. will tolerate neutral soil they grow best in slightly acidic soil. Over time they alter the soil reaction and lower the pH slightly. That’s why rookie blueberry foragers are told to look for pine forest to begin their hunt.
I envy some of our members who are on isolated pockets of acidic soil. When I started in the 80s, like every other gardener, I was told to amend my bed with liberal amount of peat moss before planting. I did that. A season of optimism soon turned sour when I inherited nothing but frustration and anguish. The pH of the black Chernozemic soil in Edmonton and immediate surrounding area is around 7.2 or higher. With high OM and clay it is very difficult to amend and maintain the adjusted pH for long: the upward moisture movement soon increases the pH within a couple of years. A couple of specialists suggested application of aluminium sulphate but I was hesitant because excess of aluminium leads to toxicity that can make growing any plants very, very difficult. Sulphur was also recommended but sulphur takes too many years to affect soil pH changes. Almost all blueberry plants sold in Alberta are hybrids between the low sweet x highbush blueberries - V. angustifolium x V. corymbosum. Although most literature listed them as hardy to Zone 3 results are very, very inconsistent and disappointing. The plants survived but suffered from severe winterkill(1). Since the initiated floral buds are on last year’s wood winterkill meant no flowers and berries. By the early 90s I gave up growing blueberries.
I was transferred to Brooks in 2002. The end of spring sales was too good to pass and I ended buying a Northblue and a Northline blueberry plants. The brown Chernozemic soil in my yard was not only alkaline but also slightly saline. Since I was already into bonsai or penjing I decided to grow the two plants in containers. The small volume of soil in container is so much easier to adjust and maintain. The other reason is providing extra winter protection is a breeze when plants are planted in containers. In fall before the snow flies I placed the pots on its side and cover the canes with fallen leaves collected from other trees. Snow added more insulation. By resisting the temptation to uncover the plants as soon as the snow had melted in spring, I have been harvesting blueberries since then (2).
Acidic soil restricts the availability of many nutrients. Blueberries overcome that by developing a symbiotic relationship with mycorrhizae, a soil dwelling fungus. As such do not wash off any soil that come with your purchased plants. If you dig from the wild, be sure to bring home some soil with your dug out plants. I mix my own potting soil using equal volume of play sand, peat moss and soil from my yard. How do I keep the pH low? I water with Ammonium sulphate in spring and fertigate with water soluble fertilizers formulated for roses or evergreens every 7 to 10 days from June to end of August. To avoid building up the salinity I use ¼ of the recommended rate. For daily watering I try not to use tap water since Edmonton’s supply is alkaline. I either use rainwater collected from the roof into barrels or I use ‘rice’ water. (I collect water used for washing rice before cooking or pasta water (without salt) and allow it to ferment for several days.) Instead of throwing away the water used for rinsing milk containers, I use it to water my blueberry or lingonberry plants (3).
I do not have honey bees in my yard and as such I do not know if honey bees are attracted to blueberry’s flowers. So far I noticed that the various bumblebees are the only native bees that work among my blueberries.
(1) I found even the local velvet leaf blueberry suffered winterkill unless it is under snow.
(2) In truth I pick very little; my grandchildren beat me to the berries every year.
(3) Milk not only helps to lower pH when it sours but also is beneficial to soil microbes.
Footnote
If you have success growing blueberries in other ways, please share your secrets. Other growers will appreciate your generosity. Last year I met a gardener who dug down to two feet and lined the bottom and sides with plastic. After punching a few holes at the bottom to allow excess water to drain out he filled it with purchased potting soil. With this method he needs not water his plants every day. For winter protection he erected a wall with chicken wire netting around his blueberry plants and filled it with leaves or straw.
There are other berries that are easily grown in Alberta. These berries not only have just as much or more antioxidants than blueberries they are also much less demanding. Saskatoon, black elderberry, black currant, Aronia and haskap are excellent examples. So if you do not want to go through the hassle of watering container grown blueberry every day, plant these alternatives instead.
Sassed of the Past By Gabe Botar added Sept. 26, 2018
When in 1977 I started working for the organization then known as the Department of Plant Science at the University of Alberta, I quickly became enamoured of the Department's large fruit orchard.
The orchard was then located on the site now occupied by the J.G. O'Donoghue Building, which came about after the sale of U of A land to the Province of Alberta. Much of the orchard could not be moved so seedlings were budded and planted at the U of A's South Campus Crops Unit in 1984. The new small germplasm repository suffered serious setbacks from the beginning and had to be terminated in the nineties. An attempt to save at least some of the unique germplasm resulted in the new mini-orchard now (since 2015) operated by the Green and Gold Garden .
Over the years, the U of A has introduced a number of useful and profitable plant lines, especially in field crops such as wheat and canola. I became interested in the fate of the few fruit introductions effected by the U of A and so came across mention of two apple cultivars, 'George' and 'Harcourt'. I had been able to taste the Harcourt and found it to be an excellent little summer apple...but there was no trace of the 'George' anywhere. What had happened to it?
Well, apparently a Mr. Robert George had planted a McIntosh seedling around 1934 and found the fruit to be medium to large (up to 7cm across), similar to Staymared, frost-resistant and of high quality. It would store until late winter and the mother tree itself was deemed to be well-formed and fire blight-resistant. The U of A purchased the tree for $1000 and released scions for testing at various prairie sites in 1948. Unfortunately, the data collected at those sites painted a somewhat less flattering picture of the fruit: it was smallish (6cm across), large-cored, and not a particularly good keeper. The verdict: there were other more promising apple lines for the prairies. The 'George' faded into oblivion...
Now the 'Harcourt', released in 1955 and still found here and there, apparently has fruit that is very similar in size, shape and colour to the 'George' of the test sites. It is interesting to note that it was named after Prof. George Harcourt, who taught horticulture at the U of A from 1915 until 1935. This little apple is definitely not a McIntosh seedling and it is not a good keeper...but to this day there are few prairie apples that can match it for quality when it is eaten out of hand at the correct degree of ripeness.
The passing years have seen both changes and stability at the Green and Gold Garden orchard: PF-47 became 'Red Sparkle', PF-51 is now 'Norkent'...and the 'Dolgo' crabapple is still one of the best for jelly. The old (and obsolete, according to some) 'Heyer 12' is still around and also appreciated for its cold-hardiness, heavy yields most years, pinkish jelly (if one ignores the maggots in the raw fruit) and good applesauce in a maggotless year...
Stories of individual fruit lines abound and sometimes evoke nostalgia for times past. Perhaps hearing these tales will open our eyes to the ever-present danger of losing cultivars that were cherished by our forebears and may yet be cherished again by those who follow us...
The orchard was then located on the site now occupied by the J.G. O'Donoghue Building, which came about after the sale of U of A land to the Province of Alberta. Much of the orchard could not be moved so seedlings were budded and planted at the U of A's South Campus Crops Unit in 1984. The new small germplasm repository suffered serious setbacks from the beginning and had to be terminated in the nineties. An attempt to save at least some of the unique germplasm resulted in the new mini-orchard now (since 2015) operated by the Green and Gold Garden .
Over the years, the U of A has introduced a number of useful and profitable plant lines, especially in field crops such as wheat and canola. I became interested in the fate of the few fruit introductions effected by the U of A and so came across mention of two apple cultivars, 'George' and 'Harcourt'. I had been able to taste the Harcourt and found it to be an excellent little summer apple...but there was no trace of the 'George' anywhere. What had happened to it?
Well, apparently a Mr. Robert George had planted a McIntosh seedling around 1934 and found the fruit to be medium to large (up to 7cm across), similar to Staymared, frost-resistant and of high quality. It would store until late winter and the mother tree itself was deemed to be well-formed and fire blight-resistant. The U of A purchased the tree for $1000 and released scions for testing at various prairie sites in 1948. Unfortunately, the data collected at those sites painted a somewhat less flattering picture of the fruit: it was smallish (6cm across), large-cored, and not a particularly good keeper. The verdict: there were other more promising apple lines for the prairies. The 'George' faded into oblivion...
Now the 'Harcourt', released in 1955 and still found here and there, apparently has fruit that is very similar in size, shape and colour to the 'George' of the test sites. It is interesting to note that it was named after Prof. George Harcourt, who taught horticulture at the U of A from 1915 until 1935. This little apple is definitely not a McIntosh seedling and it is not a good keeper...but to this day there are few prairie apples that can match it for quality when it is eaten out of hand at the correct degree of ripeness.
The passing years have seen both changes and stability at the Green and Gold Garden orchard: PF-47 became 'Red Sparkle', PF-51 is now 'Norkent'...and the 'Dolgo' crabapple is still one of the best for jelly. The old (and obsolete, according to some) 'Heyer 12' is still around and also appreciated for its cold-hardiness, heavy yields most years, pinkish jelly (if one ignores the maggots in the raw fruit) and good applesauce in a maggotless year...
Stories of individual fruit lines abound and sometimes evoke nostalgia for times past. Perhaps hearing these tales will open our eyes to the ever-present danger of losing cultivars that were cherished by our forebears and may yet be cherished again by those who follow us...
Jo Granger's note- Check out this Green and Gold Garden webpage and Gabe Botar's contribution to fruit
https://www.greengoldgarden.com/produce-for-august-14-and-18-2018/
https://www.greengoldgarden.com/produce-for-august-14-and-18-2018/
DBG Fruit Growers’ Bulletin 1-18 added Feb. 12, 2018
Interstems By Thean Pheh added Feb. 12, 2018
In the last issue, we discussed delayed incompatibility in inter-genera grafting. To a certain extent this problem can be quite easily solved with an interstem. The process involves double grafting (some refer to this as double working) where a variety that is fully compatible with two varieties are used as the ‘Mr. In Between’. That was what Bernie was talking about when he wrote about using two apple cultivars, Winter Banana and Palmetta, grafted on apple rootstocks before grafting the pears. The concept of using a Mr. In Between is not new; it had been practiced since ‘God knows when’. At one time it was widely used in the pear industry. The quince rootstock used in the old days would not accept the Bartlett pear, one of the most popular and widely planted in the world. However it is fully compatible with Old Home pear and Old Home is fully compatible with Bartlett. So to overcome the rejection growers used Old Home as the interstem. (With better and more suitable quince and other rootstocks now available I believe this practice is no longer used.)
Besides overcoming incompatibility and delayed incompatibility, interstem is useful for other purposes. M9 is the most widely used dwarfing apple rootstock in the world. It is very precocious but unfortunately has very poor root systems that cannot provide sufficient anchorage. (They must be supported for life either with individual stakes or wires.) So, someone came up with the idea of double working - using non-dwarfing rootstocks like M106 to provide good anchorage, grafting M9 onto it and then grafting the desired cultivar onto the M9. In this way well anchored dwarfing precocious apple trees are produced. (Who says you cannot have your cake and eat it too?) Unfortunately they soon ran into problems because the results were inconsistent and most plantings did not produced the desirable dwarfing effects. That resulted in heated debates on the wisdom of using double working for this purpose. It was later found that the length of the interstem played a critical role in the dwarfing effect. There must be a minimum of 8 inches for interstock for the dwarfing effect to kick in. (With today’s practice of ultra-high density planting commercial growers prefer to stake their trees instead of double working.)
Is interstem of any use to us on the harsh prairie? Most growers in Saskatchewan and a handful in Alberta use O3 or V3 as rootstocks. However O3 is not suitable in all areas. I find its stem is hardy but the roots are not; the roots must have consistent snow cover throughout winter. V3 was tested at CDCN for five years. Results were very encouraging but there is insufficient data to say with any confidence as far as its hardiness is concerned*. Gardeners in metropolitan Edmonton will have no problem with O3 or V3. However double working still merits consideration since we are in very windy country and strong gusts are frequent. In my opinion double working is definitely worth looking into for those living in Edmonton who want well anchored precocious dwarfing apple trees. Gardeners living outside the city or in rural areas may have no choice or will get better chances with double worked trees if precocious dwarfing apple/crabapple trees are desirable.
* O3 was among one of the rootstocks used as control. They failed before the test ended. Data from five years is insufficient for such long term cultural trial.
Enthusiasts of Bonsai, Penjing or container growing may find interstem useful. Malus spp. grown in containers are prime candidates for winterkill. More often than not the tops come through winter without injury but it is the roots that are completely killed. Using open pollinated seedlings as rootstocks I experienced much anguish over the years. I found most are killed in test winters but some are capable of tolerating the extremely cold even when the containers are not buried for added protection. My most hardy is an open pollination Viking crab. It was seeded in a container and after 21 years it is still very healthy without added winter protection. McIntosh grafted on it in 1997 is still productive while those grafted onto O3 and others died in one, at most three winters. In each and every case the buds began to move but dried up soon because the roots were dead. (In some cases the rootstocks were dead to the soil line and others were dead to the union.) Unfortunately this very hardy rootstock is neither dwarfing nor precocious.
Another potential commercial application is for disease control although I do not see any application for us. Rubber tree, Heavea brazillensis, is native to the Amazon Basin in Brazil. However Brazil lost its status as a major producer of rubber after Henry Wickham successfully smuggled some seeds out of the Orinoco Basin. Trees in Brazil are susceptible to a deadly disease known as the South American Leaf Blight (SALB), Microcyclus ulei. (Malaysia together with Indonesia, where SALB is absent, produce over 80% of the world’s natural rubber.) The useful or productive part of the rubber tree is the trunk. Since rubber cannot be propagated with stem cuttings, many Malaysian growers graft selected clones onto PBIG rootstocks. Unfortunately the crown of modern high yielding clones like the RIM 600 Series are very susceptible to this deadly disease. RRIM (Rubber Research Institute of Malaysia&) found a SALB resistant selection but it is totally useless because it is an extremely poor latex producer. Hence they embarked on the biggest double working trial in the world by testing the feasibility of having compound trees with 4 inches of PBIG, 8 to 10 feet of RRIM 604 and the rest of the top is the SALB resistant selection^. (The reason for the long interstem is because in harvesting only the bottom 8 feet of the trunk is tapped for the latex.)
& RRIM is the largest research institution in the world devoted to a single crop.
^ I do not know the results or the status of this trial because I left the country a few years after the trial was initiated.
Many of us are adding new cultivars to branches of existing trees. If the trees are on their own roots we are stem building. Agriculture Canada used to recommend using Malus baccata ‘Nertchinsk’ for stem building to impart winter hardiness. Most of us plant grafted trees and are merely adding more cultivars onto existing branches. Hence in a way we are using our grafted trees as the interstems. A word of caution is warrantied; multiple cultivars trees must be pruned carefully to avoid excessive growth and vigor of one cultivar to the detriment of another because some cultivars are more vigorous or compatible than others with the interstem.
This and That
Thank you, Dr. Ken Fry for responding to the last issue. Since almost all of us have saskatoon in our yard this information is of tremendous value.
Dr. Fry wrote. “As for WEA and its impact on saskatoons, they are most damaging to the establishment of saskatoon seedlings but in some research trials I did at CDC-North, I treated saskatoons with orthene to kill the aphids on the roots of saskatoons and left other saskatoons untreated and then recorded the yield over a period of 5 years. In the treated saskatoons, by year 3 the yield was significantly higher than the untreated. Therefore, while mature saskatoons will not likely be killed by WEA on the roots, the yield is negatively impacted. This can also be interpreted as indicating that WEA is a stress factor for mature saskatoon bushes.”
If you are thinking of propagating your own rootstocks please be aware that Ottawa #3 (better known as O3) is a public domain while V3 is a proprietary material.
Besides overcoming incompatibility and delayed incompatibility, interstem is useful for other purposes. M9 is the most widely used dwarfing apple rootstock in the world. It is very precocious but unfortunately has very poor root systems that cannot provide sufficient anchorage. (They must be supported for life either with individual stakes or wires.) So, someone came up with the idea of double working - using non-dwarfing rootstocks like M106 to provide good anchorage, grafting M9 onto it and then grafting the desired cultivar onto the M9. In this way well anchored dwarfing precocious apple trees are produced. (Who says you cannot have your cake and eat it too?) Unfortunately they soon ran into problems because the results were inconsistent and most plantings did not produced the desirable dwarfing effects. That resulted in heated debates on the wisdom of using double working for this purpose. It was later found that the length of the interstem played a critical role in the dwarfing effect. There must be a minimum of 8 inches for interstock for the dwarfing effect to kick in. (With today’s practice of ultra-high density planting commercial growers prefer to stake their trees instead of double working.)
Is interstem of any use to us on the harsh prairie? Most growers in Saskatchewan and a handful in Alberta use O3 or V3 as rootstocks. However O3 is not suitable in all areas. I find its stem is hardy but the roots are not; the roots must have consistent snow cover throughout winter. V3 was tested at CDCN for five years. Results were very encouraging but there is insufficient data to say with any confidence as far as its hardiness is concerned*. Gardeners in metropolitan Edmonton will have no problem with O3 or V3. However double working still merits consideration since we are in very windy country and strong gusts are frequent. In my opinion double working is definitely worth looking into for those living in Edmonton who want well anchored precocious dwarfing apple trees. Gardeners living outside the city or in rural areas may have no choice or will get better chances with double worked trees if precocious dwarfing apple/crabapple trees are desirable.
* O3 was among one of the rootstocks used as control. They failed before the test ended. Data from five years is insufficient for such long term cultural trial.
Enthusiasts of Bonsai, Penjing or container growing may find interstem useful. Malus spp. grown in containers are prime candidates for winterkill. More often than not the tops come through winter without injury but it is the roots that are completely killed. Using open pollinated seedlings as rootstocks I experienced much anguish over the years. I found most are killed in test winters but some are capable of tolerating the extremely cold even when the containers are not buried for added protection. My most hardy is an open pollination Viking crab. It was seeded in a container and after 21 years it is still very healthy without added winter protection. McIntosh grafted on it in 1997 is still productive while those grafted onto O3 and others died in one, at most three winters. In each and every case the buds began to move but dried up soon because the roots were dead. (In some cases the rootstocks were dead to the soil line and others were dead to the union.) Unfortunately this very hardy rootstock is neither dwarfing nor precocious.
Another potential commercial application is for disease control although I do not see any application for us. Rubber tree, Heavea brazillensis, is native to the Amazon Basin in Brazil. However Brazil lost its status as a major producer of rubber after Henry Wickham successfully smuggled some seeds out of the Orinoco Basin. Trees in Brazil are susceptible to a deadly disease known as the South American Leaf Blight (SALB), Microcyclus ulei. (Malaysia together with Indonesia, where SALB is absent, produce over 80% of the world’s natural rubber.) The useful or productive part of the rubber tree is the trunk. Since rubber cannot be propagated with stem cuttings, many Malaysian growers graft selected clones onto PBIG rootstocks. Unfortunately the crown of modern high yielding clones like the RIM 600 Series are very susceptible to this deadly disease. RRIM (Rubber Research Institute of Malaysia&) found a SALB resistant selection but it is totally useless because it is an extremely poor latex producer. Hence they embarked on the biggest double working trial in the world by testing the feasibility of having compound trees with 4 inches of PBIG, 8 to 10 feet of RRIM 604 and the rest of the top is the SALB resistant selection^. (The reason for the long interstem is because in harvesting only the bottom 8 feet of the trunk is tapped for the latex.)
& RRIM is the largest research institution in the world devoted to a single crop.
^ I do not know the results or the status of this trial because I left the country a few years after the trial was initiated.
Many of us are adding new cultivars to branches of existing trees. If the trees are on their own roots we are stem building. Agriculture Canada used to recommend using Malus baccata ‘Nertchinsk’ for stem building to impart winter hardiness. Most of us plant grafted trees and are merely adding more cultivars onto existing branches. Hence in a way we are using our grafted trees as the interstems. A word of caution is warrantied; multiple cultivars trees must be pruned carefully to avoid excessive growth and vigor of one cultivar to the detriment of another because some cultivars are more vigorous or compatible than others with the interstem.
This and That
Thank you, Dr. Ken Fry for responding to the last issue. Since almost all of us have saskatoon in our yard this information is of tremendous value.
Dr. Fry wrote. “As for WEA and its impact on saskatoons, they are most damaging to the establishment of saskatoon seedlings but in some research trials I did at CDC-North, I treated saskatoons with orthene to kill the aphids on the roots of saskatoons and left other saskatoons untreated and then recorded the yield over a period of 5 years. In the treated saskatoons, by year 3 the yield was significantly higher than the untreated. Therefore, while mature saskatoons will not likely be killed by WEA on the roots, the yield is negatively impacted. This can also be interpreted as indicating that WEA is a stress factor for mature saskatoon bushes.”
If you are thinking of propagating your own rootstocks please be aware that Ottawa #3 (better known as O3) is a public domain while V3 is a proprietary material.
DBG Fruit Growers’ Bulletin 3-17 added Sept. 4, 2017
Budding and Grafting Tidbits By Thean Pheh added Sept. 4, 2017
There is a universal system of classifying plants and animals. Normally only the bottom three, Genus, Species and cultivar, are mentioned. There is also a system of writing whereby the Genus and Species are written in italic and the cultivar is normal within a single quotation. For example the crabapple Columbia is written as Malus baccata ‘Columbia’. (Notice the first letter of the Genus is in uppercase while that of the Species is in the lower case.) It is a member of the Rose Family but the Family is not noted as it is assumed the reader either already knows what it is or where to find it.
Normally grafting is done between the cultivars (aka inter-cultivar grafting), for example grafting Malus baccata ‘Columbia’ onto Malus baccata ‘Renetka’. This presents the least problem. Inter-species grafts like Malus domestica ‘Goodland’ onto Malus baccata ‘Renetka’ are also very successful. Most of us are doing this. (My Heyer 12 grafted onto an open pollinated crab is over 60 years old and still very healthy and productive.) Inter-genera grafts tend to experience delayed incompatibility. Nonetheless they are widely used by commercial pear growers around the world where pears, Pyrus communis, are grafted onto quince, Cydonia oblongata. There is no record of any successful grafting outside the Family.
Most of us are growing fruits in the Rose Family like apples, pears, saskatoons, cherries, plums etc. Now, don’t jump too far ahead, yet. The Rose Family is very big and complicated with several subdivisions. Apples, pears and saskatoon belong to Maleae or pome tribe or subfamily while cherries, plums belong to the Prunoideae or stone fruit tribe. Members of the two tribes/subfamilies are not compatible: sorry you cannot graft apples onto plums.
Inter-genera grafting is widely practiced but is rarely publicized. Forced by very limited suitable land available for agriculture Korean, Japanese and Chinese farmers had been planting the same crop yearly, some for over a thousand years. That led to disease buildup in the soil. The only biological method to overcome the problem was to graft onto disease resistant rootstock. They have been grafting melons, Cucumis and watermelons, Citrullus onto various Cucurbita squashes before WW II. In Canada inter-genera grafting is not new either. It was tested by Agriculture Canada on apples, pears and other fruits after the war. As late as the early 1990s, grafting saskatoon (Amelanchier) onto cotoneaster (Cotoneaster) was the only mean of propagation for farmers in the Prairie Provinces.
Gabe Botar has experimented with inter-genera grafting for many years. Other members like Wayne Fuhr, Evelyn Mellot and Bernie Nikolai have also tested inter-genera graft for some time. Using cotoneaster as rootstock is not new in Canada. It was abandoned for valid reasons or as other better and cheaper methods of propagation become available. Nevertheless, the possibility of copying the Russians in Siberia of using cotoneaster as a rootstock for pears is worth revisiting. As with most inter-genera grafts there is delayed incompatibility. Luckily and thankfully the Russians have broken the ground for us. Let us take a short moment to understand the ins and outs of this phenomenon.
Most people think roots absorb water and nutrients from the soil. In reality only the very tiny, temporary and fragile root hairs (tiny strands of single cell found radiating from the tips of new elongating roots) are capable of performing this task or forming any relationship with beneficial soil microbes like mycorrhizae. The raw ingredients (RI) namely water and nutrients plus some hormones then travel in the xylems, found in the roots and stem, to the leaves. (The xylems are just a series of microscopic tubes found in new wood of woody plants and stem of herbaceous plants.) Through photosynthesis the leaves combine the RI with carbon (in atmospheric carbon dioxide) to produce manufactured products (MP) such as sugars, carbohydrates, proteins and other phyto-chemicals to feed the rest of the plants. These MPs travel through another series of microscopic tubes called the phloem found in the stems of all plants and easily visible as the living barks of woody trees. The roots, trunks and stems (aside from the root hairs, buds and leaves) are merely there for anchorage and to serve as conduits for transporting the RIs and MPs, and storages for excess MPs.
Thus there is a well defined system of ‘you feed me, I feed you’ or ‘you scratch my back I’ll scratch yours’. However when a plant is grafted this free flow is impeded, even in the most compatible graft. Budding or grafting involves two individual plants with different genes, abilities and habits. (Refer to earlier bulletins in 2014 and 2016.) Although each still maintains its own genetics there are sufficient interactions between the two to alter each other’s physical expressions. The impediment is at the union where connectivity is restricted or interrupted. In some cases it involves the xylem while in others it’s the phloem. When the impediment is not severe there is ‘give and take’ and the grafted plant is healthy, productive and long lived. Severe impediment results in delayed incompatibility. Delayed incompatibility is expressed differently in different grafts. Some grow well while others are unthrifty. Nevertheless, in either case the plants are short lived.
In most cases the rootstocks are on the short end of the stick. Somehow or other there is a ‘bottleneck’ in the phloem system at the union. Without sufficient MPs the roots are starved to death, or are weakened to a point that undermines their winter hardiness or predisposes them to diseases. With annuals, farmers in Korea, Japan and China have no choice but to use only fully compatible rootstocks. Since we are dealing with trees – very long-lived perennials - more options are available to us. The easiest way to overcome the starvation is to break the standard rule of removing all suckers from the rootstock. For lack of a better word or to differentiate these suckers from the undesirable ones we call these ‘nurse suckers’, just because they are in reality nursing the roots with MPs.
The reason for the standard recommendation of removing suckers from rootstock is to prevent the rootstock from taking over. Hence when nurse suckers are used in inter-genera grafts growers must be vigilant and checked the growth of nurse suckers yearly. How many suckers and how vigorous can nurse suckers be allowed to grow is still anyone guess. The Russians may have it pecked down to 1/3 of the whole tree but their results may not be fully applicable to our growing conditions or modus operandi. Hence more work is needed.
Besides working out the best way to maintain or manage the nurse suckers on inter-genera grafts growers must always keep other issues in mind, especially in Alberta. Among the important ones are pest and disease resistance, and anchorage. Let’s take the case of pears grafted onto cotoneaster. There is no doubt Cotoneaster lucida is hardy but it is very attractive to oyster scale, Oyster scales are very sneaky, often blending well with the trunk and unless looked at carefully often escape notice until it’s too late. Secondly cotoneaster is very susceptible to Pink Disease, Nectria. In most literature Nectria is listed as a saprophytic disease (attacking the dead or weak) but recently some pathologists have noted it as parasitic. Wayne Fuhr and others have grafted pears onto saskatoon. The immediate problem with this combination especially in Edmonton and Calgary is related to the Wooly Elm Aphids (WEA), Eriosoma americanum. The two cities have the distinction of having the highest population and concentration of American Elm, Ulmus americana, in the world. This title comes with a very stiff price. The WEA moves from the elm leaves to feed on the saskatoon roots in summer. While the feeding itself does little damage the puncture points left behind lead to secondary infections that either cause stunted growth or death. Also, Alberta is a very windy country. Will the roots provide sufficient anchorage to gusts that go up to 100 kph? (Such gusts appear to be yearly occurrence.) If not, permanent support must be provided for the life of the tree.
Inputs from others
Thank you Gabe, Bernie and Evelyn; your contributions not only enhance this treatise but also lend creditability.
Gabe writes ‘I refer to the one surviving approx. 30-year-old 'Smokey' saskatoon tree on Sorbus americana rootstock at F64. This combination tree demonstrates a couple of points. First, with judicious pruning a saskatoon on Sorbus roots may remain healthy for longer than it would normally, on its own roots. Second, intergeneric graft compatibilities can vary greatly with the genetics of the scion and rootstock; I have seen saskatoons develop incompatibility symptoms on Sorbus seedlings within 3 years. Third, a pear branch grafted on this old 'Smokey'/Sorbus tree has been around and healthy for several years but it is nicely dwarfed ; perhaps 'Smokey' is more dwarfing than other saskatoon cultivars for pears, especially in the 'Smokey'/Sorbus configuration..’
Bernie writes ‘pear grafted on apple seems to be working well with both a Winter Banana and a Palmetta interstem. Palmetta will be better as it is very hardy and took -50F without tip dieback in Fairbanks, Alaska. Half my Winter Banana interstems died this winter, plus the pears grafted to them, and it was a mild winter too!’
Evelyn writes about her pears. ‘I have a lot better luck with grafting onto cotoneaster compared to others such as saskatoon, hawthorne. I have grafted onto both saskatoon and hawthorn but after a couple years they die, the longest one was one was a saskatoon at 4 years. Maybe it's because I have been using "Large" rootstock of the saskatoon and hawthorn (like grafting onto a branch/main stem ) and for the cotoneaster it has always been small rootstock and grafting 6 to eight inches from the ground. Touch wood, so far the only pear on cotoneaster I lost was one that I did not keep the cotoneaster rootstock trimmed. I don't remove any of the shoots/ branches that grow, but I do always keep them hedged short. I try to keep them hedged around 6 - 8 inches from the ground.
On new grafts I always keep them above the rootstock, never letting the rootstock grow taller than the graft.
I do trim the "pear" tree to maintain a 5 to 7 foot tree and try to keep it from getting top heavy. I would hate for it to break at the graft and not sure how much of a top (pear) that this rootstock can support. I have a tiny quince tree (I started from seed and so far our winters has keep it a bush) that I grafted to a cotoneaster this spring. Be interesting to see if the cotoneaster can pass on some of its hardiness to the quince. I also have an apple and Gabe’s compatible mountain ash grafted to cotoneaster, going on three years and doing well. I have maybe 10 other pear/cotoneaster grafts, 2 to 3 years old. So far I have not seen incompatibility issues.’
Footnote,
* I have received two responses to the article of plum pollination. Thank you, Rene and Arumugam.
* I am one of the unintended victims of Edmonton’s beautification program. Surrounded by fully matured American elms, perhaps over 70 years old, I cannot grow saskatoon on its own roots and have to resort to grafting. My Lee 13 grafted onto cotoneaster did not present any problem. Those grafted onto mountain ashes, Sorbus aucuparia and S. americana, grew very well but died within three years when no nurse suckers were permitted. The two latest grafts where nurse suckers are allowed are still very healthy and productive after four years.
* In issue #3-16, I wrote about my ‘wormy apricot’. Well the mystery is solved. It’s the apple maggot that was the culprit. Guess what? It is at it again. I have another good crop this year and every apricot has a maggot or two. On the subject of apple maggot, in issue #1-17 I noted we had three consecutive years that are not conducive to the insect. This year I have the lowest population in last three years; most of my ‘trap crop’ of Heyer 12, Norkent and Rescue, were left unmolested. (These three cultivars were the most attractive to apple maggots in my yard.)
Normally grafting is done between the cultivars (aka inter-cultivar grafting), for example grafting Malus baccata ‘Columbia’ onto Malus baccata ‘Renetka’. This presents the least problem. Inter-species grafts like Malus domestica ‘Goodland’ onto Malus baccata ‘Renetka’ are also very successful. Most of us are doing this. (My Heyer 12 grafted onto an open pollinated crab is over 60 years old and still very healthy and productive.) Inter-genera grafts tend to experience delayed incompatibility. Nonetheless they are widely used by commercial pear growers around the world where pears, Pyrus communis, are grafted onto quince, Cydonia oblongata. There is no record of any successful grafting outside the Family.
Most of us are growing fruits in the Rose Family like apples, pears, saskatoons, cherries, plums etc. Now, don’t jump too far ahead, yet. The Rose Family is very big and complicated with several subdivisions. Apples, pears and saskatoon belong to Maleae or pome tribe or subfamily while cherries, plums belong to the Prunoideae or stone fruit tribe. Members of the two tribes/subfamilies are not compatible: sorry you cannot graft apples onto plums.
Inter-genera grafting is widely practiced but is rarely publicized. Forced by very limited suitable land available for agriculture Korean, Japanese and Chinese farmers had been planting the same crop yearly, some for over a thousand years. That led to disease buildup in the soil. The only biological method to overcome the problem was to graft onto disease resistant rootstock. They have been grafting melons, Cucumis and watermelons, Citrullus onto various Cucurbita squashes before WW II. In Canada inter-genera grafting is not new either. It was tested by Agriculture Canada on apples, pears and other fruits after the war. As late as the early 1990s, grafting saskatoon (Amelanchier) onto cotoneaster (Cotoneaster) was the only mean of propagation for farmers in the Prairie Provinces.
Gabe Botar has experimented with inter-genera grafting for many years. Other members like Wayne Fuhr, Evelyn Mellot and Bernie Nikolai have also tested inter-genera graft for some time. Using cotoneaster as rootstock is not new in Canada. It was abandoned for valid reasons or as other better and cheaper methods of propagation become available. Nevertheless, the possibility of copying the Russians in Siberia of using cotoneaster as a rootstock for pears is worth revisiting. As with most inter-genera grafts there is delayed incompatibility. Luckily and thankfully the Russians have broken the ground for us. Let us take a short moment to understand the ins and outs of this phenomenon.
Most people think roots absorb water and nutrients from the soil. In reality only the very tiny, temporary and fragile root hairs (tiny strands of single cell found radiating from the tips of new elongating roots) are capable of performing this task or forming any relationship with beneficial soil microbes like mycorrhizae. The raw ingredients (RI) namely water and nutrients plus some hormones then travel in the xylems, found in the roots and stem, to the leaves. (The xylems are just a series of microscopic tubes found in new wood of woody plants and stem of herbaceous plants.) Through photosynthesis the leaves combine the RI with carbon (in atmospheric carbon dioxide) to produce manufactured products (MP) such as sugars, carbohydrates, proteins and other phyto-chemicals to feed the rest of the plants. These MPs travel through another series of microscopic tubes called the phloem found in the stems of all plants and easily visible as the living barks of woody trees. The roots, trunks and stems (aside from the root hairs, buds and leaves) are merely there for anchorage and to serve as conduits for transporting the RIs and MPs, and storages for excess MPs.
Thus there is a well defined system of ‘you feed me, I feed you’ or ‘you scratch my back I’ll scratch yours’. However when a plant is grafted this free flow is impeded, even in the most compatible graft. Budding or grafting involves two individual plants with different genes, abilities and habits. (Refer to earlier bulletins in 2014 and 2016.) Although each still maintains its own genetics there are sufficient interactions between the two to alter each other’s physical expressions. The impediment is at the union where connectivity is restricted or interrupted. In some cases it involves the xylem while in others it’s the phloem. When the impediment is not severe there is ‘give and take’ and the grafted plant is healthy, productive and long lived. Severe impediment results in delayed incompatibility. Delayed incompatibility is expressed differently in different grafts. Some grow well while others are unthrifty. Nevertheless, in either case the plants are short lived.
In most cases the rootstocks are on the short end of the stick. Somehow or other there is a ‘bottleneck’ in the phloem system at the union. Without sufficient MPs the roots are starved to death, or are weakened to a point that undermines their winter hardiness or predisposes them to diseases. With annuals, farmers in Korea, Japan and China have no choice but to use only fully compatible rootstocks. Since we are dealing with trees – very long-lived perennials - more options are available to us. The easiest way to overcome the starvation is to break the standard rule of removing all suckers from the rootstock. For lack of a better word or to differentiate these suckers from the undesirable ones we call these ‘nurse suckers’, just because they are in reality nursing the roots with MPs.
The reason for the standard recommendation of removing suckers from rootstock is to prevent the rootstock from taking over. Hence when nurse suckers are used in inter-genera grafts growers must be vigilant and checked the growth of nurse suckers yearly. How many suckers and how vigorous can nurse suckers be allowed to grow is still anyone guess. The Russians may have it pecked down to 1/3 of the whole tree but their results may not be fully applicable to our growing conditions or modus operandi. Hence more work is needed.
Besides working out the best way to maintain or manage the nurse suckers on inter-genera grafts growers must always keep other issues in mind, especially in Alberta. Among the important ones are pest and disease resistance, and anchorage. Let’s take the case of pears grafted onto cotoneaster. There is no doubt Cotoneaster lucida is hardy but it is very attractive to oyster scale, Oyster scales are very sneaky, often blending well with the trunk and unless looked at carefully often escape notice until it’s too late. Secondly cotoneaster is very susceptible to Pink Disease, Nectria. In most literature Nectria is listed as a saprophytic disease (attacking the dead or weak) but recently some pathologists have noted it as parasitic. Wayne Fuhr and others have grafted pears onto saskatoon. The immediate problem with this combination especially in Edmonton and Calgary is related to the Wooly Elm Aphids (WEA), Eriosoma americanum. The two cities have the distinction of having the highest population and concentration of American Elm, Ulmus americana, in the world. This title comes with a very stiff price. The WEA moves from the elm leaves to feed on the saskatoon roots in summer. While the feeding itself does little damage the puncture points left behind lead to secondary infections that either cause stunted growth or death. Also, Alberta is a very windy country. Will the roots provide sufficient anchorage to gusts that go up to 100 kph? (Such gusts appear to be yearly occurrence.) If not, permanent support must be provided for the life of the tree.
Inputs from others
Thank you Gabe, Bernie and Evelyn; your contributions not only enhance this treatise but also lend creditability.
Gabe writes ‘I refer to the one surviving approx. 30-year-old 'Smokey' saskatoon tree on Sorbus americana rootstock at F64. This combination tree demonstrates a couple of points. First, with judicious pruning a saskatoon on Sorbus roots may remain healthy for longer than it would normally, on its own roots. Second, intergeneric graft compatibilities can vary greatly with the genetics of the scion and rootstock; I have seen saskatoons develop incompatibility symptoms on Sorbus seedlings within 3 years. Third, a pear branch grafted on this old 'Smokey'/Sorbus tree has been around and healthy for several years but it is nicely dwarfed ; perhaps 'Smokey' is more dwarfing than other saskatoon cultivars for pears, especially in the 'Smokey'/Sorbus configuration..’
Bernie writes ‘pear grafted on apple seems to be working well with both a Winter Banana and a Palmetta interstem. Palmetta will be better as it is very hardy and took -50F without tip dieback in Fairbanks, Alaska. Half my Winter Banana interstems died this winter, plus the pears grafted to them, and it was a mild winter too!’
Evelyn writes about her pears. ‘I have a lot better luck with grafting onto cotoneaster compared to others such as saskatoon, hawthorne. I have grafted onto both saskatoon and hawthorn but after a couple years they die, the longest one was one was a saskatoon at 4 years. Maybe it's because I have been using "Large" rootstock of the saskatoon and hawthorn (like grafting onto a branch/main stem ) and for the cotoneaster it has always been small rootstock and grafting 6 to eight inches from the ground. Touch wood, so far the only pear on cotoneaster I lost was one that I did not keep the cotoneaster rootstock trimmed. I don't remove any of the shoots/ branches that grow, but I do always keep them hedged short. I try to keep them hedged around 6 - 8 inches from the ground.
On new grafts I always keep them above the rootstock, never letting the rootstock grow taller than the graft.
I do trim the "pear" tree to maintain a 5 to 7 foot tree and try to keep it from getting top heavy. I would hate for it to break at the graft and not sure how much of a top (pear) that this rootstock can support. I have a tiny quince tree (I started from seed and so far our winters has keep it a bush) that I grafted to a cotoneaster this spring. Be interesting to see if the cotoneaster can pass on some of its hardiness to the quince. I also have an apple and Gabe’s compatible mountain ash grafted to cotoneaster, going on three years and doing well. I have maybe 10 other pear/cotoneaster grafts, 2 to 3 years old. So far I have not seen incompatibility issues.’
Footnote,
* I have received two responses to the article of plum pollination. Thank you, Rene and Arumugam.
* I am one of the unintended victims of Edmonton’s beautification program. Surrounded by fully matured American elms, perhaps over 70 years old, I cannot grow saskatoon on its own roots and have to resort to grafting. My Lee 13 grafted onto cotoneaster did not present any problem. Those grafted onto mountain ashes, Sorbus aucuparia and S. americana, grew very well but died within three years when no nurse suckers were permitted. The two latest grafts where nurse suckers are allowed are still very healthy and productive after four years.
* In issue #3-16, I wrote about my ‘wormy apricot’. Well the mystery is solved. It’s the apple maggot that was the culprit. Guess what? It is at it again. I have another good crop this year and every apricot has a maggot or two. On the subject of apple maggot, in issue #1-17 I noted we had three consecutive years that are not conducive to the insect. This year I have the lowest population in last three years; most of my ‘trap crop’ of Heyer 12, Norkent and Rescue, were left unmolested. (These three cultivars were the most attractive to apple maggots in my yard.)
Charts above added by Jo as examples of scientific classification of different fruits
DBG Fruit Growers’ Bulletin 2-17 added June 23, 2017
Plum Pollination By Thean Pheh June 23, 2017
There are lots of information out there on pollination of plums. In my humble opinion, very few are reliable while the majority are pure garbage; garbage deduced from mathematical equation rather than actual research or fact. Many, including respected horticulturists, work on the assumption that if a=b, and b=c then a=c. I wish things are as simple as this when we are dealing with living things where each a, b, c is embedded with multiple unknown or yet to be understood variables. When it involves the hanky-panky of stone fruit, the only consensus is hardy Japanese, Japanese hybrids and Native plums (JHN) are self-sterile – hence the recommendation of planting two cultivars that resulted from the a, b, c theory. As far as I know less than a handful of horticulturists had done any real in-depth research into the subject of pollination of hardy JHN plums. University of Saskatchewan recommends the use of unnamed and unselected wild native plums as pollinator. As far back as 1927 Dr. Hansen wrote and publicized the same recommendation. (I consider Dr. N. Hansen of South Dakota University to be the authority on this subject.) There are lots of talks in the last couple of years on Toka as a pollinator. I do not have a Toka plum and have no right to say anything. (Incidentally Toka is a multiple species hybrid bred by Dr. Hansen, but he made no mention of it as a pollinator.) Aside from pollinating agents there are three parts to this subject; one is variety compatibility, the second is the virility of the pollen and the third is pollen growth. Variety compatibility refers to the acceptance of the pollen of one variety by the receiving variety. Virility refers to whether the pollen is strong or weak. Once deposited on the stigma, the pollen has to travel down the style to reach the ovule. Although the style may be just ½ to one inch long, it is a very, very, very long distance to travel for the microscopic pollen. Its speed and growth is determined by its virility and air temperature. Although I have been looking at the pollination of stone fruits for a few years I do not have the time and resources to test these three parts. Hence the little I have observed is likely to be useless; perhaps I am barking up the wrong tree. I love to hear the opinions of others.
Stone fruits like plums, cherries, cherryplums, produce perfect or hermaphrodite flowers. In other word, each flower contains both the male and female components. Since the flowers are perfect people automatically assume everything is perfect. Since insects depend on flowers to supply their daily food, principally nectar and pollen, and they have compound eyes, they are more observant than humans are and they can see things that we cannot. While looking at pollinating agents at work, I was at a complete lost as to why most native bees avoid some plants although they were loaded with big attractive blossoms. (I have not seen a honeybee in my yard for decades. Thankfully with the city allowing Edmontonians to take up apiculture I saw a handful of honeybees this year.) Konrad told me his honeybees also have the same tendency too. Could it be these plants do not produce sufficient nectar and pollen to attract these pollinating agents? What are deterring the bees? Could it be the flowers are radiating confusing ultra-violet patterns? Could it be they are emitting olfactory compounds that are offensive to the bees? Or could it be that these plants only produce the goodies at night to attract nocturnal insects?
Since JHN plums are self-sterile gardeners are told to plant any two cultivars with overlapping flowering period if they want to harvest any plums. (I am ashamed that I was forwarding this advice to gardeners in my earlier working life.) A very good example is the standard recommendations of planting Brookred with Pembina plums or Manor with Kappa cherryplums. Many gardeners did just that and have plums and cherryplums that bloom like Sakura every spring but never set any fruit. Like everyone else my first thought was varietal incompatibility; pollen of either not accepted by the ovule of the other. Sometimes I blamed the temperature - too cold for pollen growth or late frosts. Then, while trying to solve the question of why pollinating agents are avoiding some flowers and why I failed to get any fruit set with some crosses when I took up breeding for a hobby after retirement, I decided to check the flowers.
I went around every stone fruit I have or had access to. Like the budding Sherlock Holmes I worked alone in silence. (Holmes was working alone for over 7 years before John Watson became his partner.) Armed only with a tiny pocket 14x magnifying glass I check the flowers on different days and at different time during the day except after 8 pm. (Sleep is too important to me.) Like everyone else I thought everything was perfect. The complete absence of pollen on some cultivars caught me with my pants down. The anthers are nice and plump but when it is time for anthesis (when both male and female components are fully functional and receptive) I notice the anthers are completely empty without a single grain of pollen. In stone fruits the anthers revert at anthesis to expose and release the pollen but in some cultivars the anthers just revert and dry up soon. If there is already a word for this phenomenon I do not know since I slept my way through or did not show up in plant physiology classes. For this lack of knowledge I call it dry anther. Perhaps dysfunctional is more politically correct.
With this observation, in my opinion, the first step in solving the three parts to stone fruit pollination puzzle is in knowing which cultivar or variety has fully functional anthers and those with dry anthers. Once we have this we can move to the next step of solving variety compatibility. However like every gardener I am very limited because I just have a small number of varieties. If each of us were to do this little observation, we can pool our results together and come out with a dBase that might be useful. I am willing to add your observations to my existing dBase if you are interested in doing your part. In the meantime I shall not bore you with how I go about this task. But, if you are interested in contributing to this dBase please let me know and we shall discuss and refine my protocol. (Please contact me at [email protected] if you are interested in this project.) Ideally the Public Sector should be doing this work but with Alberta Agriculture abolishing the Fruit Section, we are left high and dry. If we don’t help ourselves we are merely dreaming of finding the proverbial needle in the haystack or like my father liked to put it ‘a blind chicken pecking around aimlessly hoping to find a worm’. If that’s difficult enough we are also attempting to do it in the middle of the night. If we don’t open another can of worms we will be following a blind leader every time someone suggests another pollinator.
Footnote
Unselected and unnamed Native plums have functional anthers with lots of pollen to each. That’s the only reason why Dr. Hansen and U of S recommended them as pollinators. However, they produce plums of very poor eating and processing qualities. Since there are named cultivars with functional anthers too, having pollinators that also produces good quality plums is definitely a bonus. The first task is to find them.
If indeed JHN and cherryplums are ‘night owls’ I might have missed the boat completely by hitting the sack early. If they are ‘night owls’ what are the pollinating agents?
Two blocks from my house I notice there is a house with a Pembina and a native plum growing side by side. This Pembina is so loaded with plums every year that it is a dwarf with every branch hanging down due to the weight of the plums. Yet the native plum (most probably a root sucker of the rootstock) bears very few plums or none at all in most years. The immediate neighbors’ trees to the east and west (about 100 feet away) bloom heavily every year but even at their best never set more than a handful of plums. Why? I’m still scratching my head – have the bees become fanatical locavores that they are restricting their diets to within a few feet?
I noticed another very strange phenomenon this spring. I have apricot seedlings planted a foot apart in a row that I wanted to use as rootstock for plums. I never got down to doing it. Most have died and I only have 5 plants left. All flowered this year. Two seedlings have pure white flowers and they are flanked by trees with normal pink flowers. Pollinators were all over the pink flowers but not a single went to the two with white flowers. Why? I don’t know. If you do, please enlighten me. Aren’t bees supposed to be color blind? Do the white flowers produce significant different ultra violet radiation patterns to confuse the bees?
Stone fruits like plums, cherries, cherryplums, produce perfect or hermaphrodite flowers. In other word, each flower contains both the male and female components. Since the flowers are perfect people automatically assume everything is perfect. Since insects depend on flowers to supply their daily food, principally nectar and pollen, and they have compound eyes, they are more observant than humans are and they can see things that we cannot. While looking at pollinating agents at work, I was at a complete lost as to why most native bees avoid some plants although they were loaded with big attractive blossoms. (I have not seen a honeybee in my yard for decades. Thankfully with the city allowing Edmontonians to take up apiculture I saw a handful of honeybees this year.) Konrad told me his honeybees also have the same tendency too. Could it be these plants do not produce sufficient nectar and pollen to attract these pollinating agents? What are deterring the bees? Could it be the flowers are radiating confusing ultra-violet patterns? Could it be they are emitting olfactory compounds that are offensive to the bees? Or could it be that these plants only produce the goodies at night to attract nocturnal insects?
Since JHN plums are self-sterile gardeners are told to plant any two cultivars with overlapping flowering period if they want to harvest any plums. (I am ashamed that I was forwarding this advice to gardeners in my earlier working life.) A very good example is the standard recommendations of planting Brookred with Pembina plums or Manor with Kappa cherryplums. Many gardeners did just that and have plums and cherryplums that bloom like Sakura every spring but never set any fruit. Like everyone else my first thought was varietal incompatibility; pollen of either not accepted by the ovule of the other. Sometimes I blamed the temperature - too cold for pollen growth or late frosts. Then, while trying to solve the question of why pollinating agents are avoiding some flowers and why I failed to get any fruit set with some crosses when I took up breeding for a hobby after retirement, I decided to check the flowers.
I went around every stone fruit I have or had access to. Like the budding Sherlock Holmes I worked alone in silence. (Holmes was working alone for over 7 years before John Watson became his partner.) Armed only with a tiny pocket 14x magnifying glass I check the flowers on different days and at different time during the day except after 8 pm. (Sleep is too important to me.) Like everyone else I thought everything was perfect. The complete absence of pollen on some cultivars caught me with my pants down. The anthers are nice and plump but when it is time for anthesis (when both male and female components are fully functional and receptive) I notice the anthers are completely empty without a single grain of pollen. In stone fruits the anthers revert at anthesis to expose and release the pollen but in some cultivars the anthers just revert and dry up soon. If there is already a word for this phenomenon I do not know since I slept my way through or did not show up in plant physiology classes. For this lack of knowledge I call it dry anther. Perhaps dysfunctional is more politically correct.
With this observation, in my opinion, the first step in solving the three parts to stone fruit pollination puzzle is in knowing which cultivar or variety has fully functional anthers and those with dry anthers. Once we have this we can move to the next step of solving variety compatibility. However like every gardener I am very limited because I just have a small number of varieties. If each of us were to do this little observation, we can pool our results together and come out with a dBase that might be useful. I am willing to add your observations to my existing dBase if you are interested in doing your part. In the meantime I shall not bore you with how I go about this task. But, if you are interested in contributing to this dBase please let me know and we shall discuss and refine my protocol. (Please contact me at [email protected] if you are interested in this project.) Ideally the Public Sector should be doing this work but with Alberta Agriculture abolishing the Fruit Section, we are left high and dry. If we don’t help ourselves we are merely dreaming of finding the proverbial needle in the haystack or like my father liked to put it ‘a blind chicken pecking around aimlessly hoping to find a worm’. If that’s difficult enough we are also attempting to do it in the middle of the night. If we don’t open another can of worms we will be following a blind leader every time someone suggests another pollinator.
Footnote
Unselected and unnamed Native plums have functional anthers with lots of pollen to each. That’s the only reason why Dr. Hansen and U of S recommended them as pollinators. However, they produce plums of very poor eating and processing qualities. Since there are named cultivars with functional anthers too, having pollinators that also produces good quality plums is definitely a bonus. The first task is to find them.
If indeed JHN and cherryplums are ‘night owls’ I might have missed the boat completely by hitting the sack early. If they are ‘night owls’ what are the pollinating agents?
Two blocks from my house I notice there is a house with a Pembina and a native plum growing side by side. This Pembina is so loaded with plums every year that it is a dwarf with every branch hanging down due to the weight of the plums. Yet the native plum (most probably a root sucker of the rootstock) bears very few plums or none at all in most years. The immediate neighbors’ trees to the east and west (about 100 feet away) bloom heavily every year but even at their best never set more than a handful of plums. Why? I’m still scratching my head – have the bees become fanatical locavores that they are restricting their diets to within a few feet?
I noticed another very strange phenomenon this spring. I have apricot seedlings planted a foot apart in a row that I wanted to use as rootstock for plums. I never got down to doing it. Most have died and I only have 5 plants left. All flowered this year. Two seedlings have pure white flowers and they are flanked by trees with normal pink flowers. Pollinators were all over the pink flowers but not a single went to the two with white flowers. Why? I don’t know. If you do, please enlighten me. Aren’t bees supposed to be color blind? Do the white flowers produce significant different ultra violet radiation patterns to confuse the bees?
Fruit Growing in Chetwynd, BC Zone 2b By Rene Poulin added June 23, 2017
As a new member, I thought I would take the opportunity to introduce myself and tell you what I have been doing. My homestead is in the Rocky Mountain foothills in B.C.'s Peace River region Zone 2b. Not an ideal spot, on a north slope of rocky, clay that alternates from too wet to too dry, in a rain shadow, shaded by the mountain top above me for 3 months in the winter, but has a few plus factors such as no frost pockets, good reliable snow cover, later flowering in spring, no apple maggots, etc.
I use a lot of permaculture principles and techniques in my garden, although I do not follow a step by step permaculture design format. Every part of my yard began by being tilled and planted with potatoes. In following years other vegetables were planted and then gradually berries and herbaceous perennials were introduced along with trees and shrubs. I often grow flower bulbs, garlic, onions and other less competitive annual plants directly around the trees and shrubs for the first few years. The trees then receive more attention, water, weeding, fertilizer, mulch etc and grow far more quickly than if I just plant them on a little island in a sea of grass expecting that they will magically form an idyllic orchard of vigorous productive trees growing on an unchanging lawn.
My lawn is on the endangered species list and that's the way I like it! Death to Grass is my motto. In my experience it's the best thing you can do to improve tree growth vigor. Kill the grass. Mow it, dig it, till it, smother it, lay down cardboard, hardwood chip mulch from trunk to drip line leaving space for root collars to breathe. If at some point in the future, my trees are large and overly vigorous then allowing grass to return may be an option.
My homestead trees Rescue and Norland are producing apples as well as the SK Cherries. Have lots of berries as well. I am planting 60 trees/shrubs this year. Rootstocks and pollinators are at the top of my list. Apple rootstocks: Siberian crab and Antonovka for full size trees, Bud 118 for semi dwarf, Bud 9 and Vee 3 for dwarf. Pear rootstock: Siberian pear, and cotoneaster, mountain ash for experimental dwarfs. Plum rootstock: Prunus Americana wild plum, Mustang cherry plum, Prunus nigra or Canada Plum and Western Sandcherry as pollinators and possible rootstock. Some of these are planted close together in clonal propagation beds that will be mounded in order to establish my rootstock nursery.
Norland fruiting Summer 2016 mulched wood chips growing with garlic on the right. Photo 1.
Siberian pear, Siberian crab, Bud118, and Antonovka rootstocks planted in raised beds to be stooled or mounded with soil next year to clone rootstock for grafting. Rescue crab flowering in background and top grafted with crab scions. Photo 2.
I work as a Community Garden coordinator and manage two large gardens in the Pine River valley of Chetwynd, BC , where I grow vegetables for the local farmers market along with a few nursery plants, mostly fruits, perennial vegetables, heirloom seeds and herbs. Dozens of families and Elementary school students grow gardens there as well.
The first community garden I helped develop is at our local hospital and is an ideal site for fruit. It has three large apple trees, and cherries, great southwest exposure , little frost, water, greenhouse, and a chain link fence that is deer proof. I have now completed topgrafting all 20 scions on the apples there and have planted Siberian crab and pear, Sandcherry, Nanking Cherry, and Prunus Americana as pollinators and rootstocks. This garden is functioning as a local genetic fruitbank from which fruit is grown in public view and will be propagated and distributed locally. Photo 3.
Topgrafted Rescue on the right, Romance series cherries blooming on the left. Photo 4.
Topgrafted Norland apple. Ben Nevis black currant in foreground. Cherries and Northline Saskatoon in background. Photo 5.
Last August I was introduced to a gardener named Linda, on a garden tour. She had the most amazing pair of plum trees I had ever seen in the north. They were absolutely loaded with ripe plums, and the tree suffered breaking limbs and needed surgery. Tasting northern plums for the first time ever, I was blown away by the rich flavor. Fortunately she had too many and insisted I take 50 pounds home with me!
What appear to be Pembina plums. We canned these in syrup and ate as many as we could fresh. Photo 6.
Well, I determined right then, I needed to find out more about her trees. She had forgotten what varieties she had planted, but the trees came from retail nurseries that resold wholesale trees about 15 years previous. I took pictures, and examined leaves, fruit, buds and flowers. Using the Trees of Canada field guide and info from the U of S website among others, I have been identifying the trees based on revealed characteristics that are unique to each.
We are certain that one is a Canada Plum Prunus nigra, the essential pollinator of hybrid plums. The leaves, and fruit match up. The flowers are small , white turning pinkish with time, never suckering from the roots. It is naturally semi dwarf in this climate. Linda planted this Plum, realizing after planting the first Plum that she needed a pollinator. Fortunately the nursery sold her the right tree.
Prunus nigra. Canada Plum Spring 2017. Linda's garden. Photo 7.
Prunus Nigra Canada Plum a wonderful Plum with a tart apricot flavor. Made excellent jam. August 2016. Photo 8.
Judging by the fruit, and the general availability of hybrid Plum varieties in mainstream nurseries, the biggest tree seemed closest to the description and photos of Pembina. One characteristic of this tree was that root suckers were profuse. I was given permission to dig as many as I wished. I now have ten of them growing in pots and the ground.
Linda and I assumed that the suckers were from Pembina Plum. This spring I made sure to observe the flowers closely. The Canada Plum had flowers that matched the ID keys perfectly. The Pembina had large white blossoms but the rootsuckers had formed a shrublike tree nearby that was now covered in blossoms for the first time. Small white blossoms with no pink. No fruit has yet been observed on the small tree. Maybe this year we will see some fruit and be able to be more certain of its identity. So the suckers are not Pembina but it's grafted rootstock. There are only so many species of hardy Plum that can be used as rootstock. The profuse suckering, flowers, and leaf shape are matching up with Prunus Americana and I have used it as rootstock for my Plum scions, Too early to know yet just how many grafts will take. I am hoping for at least 50 percent success. It would seem best to avoid making too many assumptions here but close observation will continue and I am certain in time the truth will be revealed.
Left : Pembina blossoms, middle: Canada Plum with pink sepals, Right: possibly Prunus Americana American Wild Plum. Photo 9.
What seems to be Prunus Americana in Linda's garden Photo 10.
I use a lot of permaculture principles and techniques in my garden, although I do not follow a step by step permaculture design format. Every part of my yard began by being tilled and planted with potatoes. In following years other vegetables were planted and then gradually berries and herbaceous perennials were introduced along with trees and shrubs. I often grow flower bulbs, garlic, onions and other less competitive annual plants directly around the trees and shrubs for the first few years. The trees then receive more attention, water, weeding, fertilizer, mulch etc and grow far more quickly than if I just plant them on a little island in a sea of grass expecting that they will magically form an idyllic orchard of vigorous productive trees growing on an unchanging lawn.
My lawn is on the endangered species list and that's the way I like it! Death to Grass is my motto. In my experience it's the best thing you can do to improve tree growth vigor. Kill the grass. Mow it, dig it, till it, smother it, lay down cardboard, hardwood chip mulch from trunk to drip line leaving space for root collars to breathe. If at some point in the future, my trees are large and overly vigorous then allowing grass to return may be an option.
My homestead trees Rescue and Norland are producing apples as well as the SK Cherries. Have lots of berries as well. I am planting 60 trees/shrubs this year. Rootstocks and pollinators are at the top of my list. Apple rootstocks: Siberian crab and Antonovka for full size trees, Bud 118 for semi dwarf, Bud 9 and Vee 3 for dwarf. Pear rootstock: Siberian pear, and cotoneaster, mountain ash for experimental dwarfs. Plum rootstock: Prunus Americana wild plum, Mustang cherry plum, Prunus nigra or Canada Plum and Western Sandcherry as pollinators and possible rootstock. Some of these are planted close together in clonal propagation beds that will be mounded in order to establish my rootstock nursery.
Norland fruiting Summer 2016 mulched wood chips growing with garlic on the right. Photo 1.
Siberian pear, Siberian crab, Bud118, and Antonovka rootstocks planted in raised beds to be stooled or mounded with soil next year to clone rootstock for grafting. Rescue crab flowering in background and top grafted with crab scions. Photo 2.
I work as a Community Garden coordinator and manage two large gardens in the Pine River valley of Chetwynd, BC , where I grow vegetables for the local farmers market along with a few nursery plants, mostly fruits, perennial vegetables, heirloom seeds and herbs. Dozens of families and Elementary school students grow gardens there as well.
The first community garden I helped develop is at our local hospital and is an ideal site for fruit. It has three large apple trees, and cherries, great southwest exposure , little frost, water, greenhouse, and a chain link fence that is deer proof. I have now completed topgrafting all 20 scions on the apples there and have planted Siberian crab and pear, Sandcherry, Nanking Cherry, and Prunus Americana as pollinators and rootstocks. This garden is functioning as a local genetic fruitbank from which fruit is grown in public view and will be propagated and distributed locally. Photo 3.
Topgrafted Rescue on the right, Romance series cherries blooming on the left. Photo 4.
Topgrafted Norland apple. Ben Nevis black currant in foreground. Cherries and Northline Saskatoon in background. Photo 5.
Last August I was introduced to a gardener named Linda, on a garden tour. She had the most amazing pair of plum trees I had ever seen in the north. They were absolutely loaded with ripe plums, and the tree suffered breaking limbs and needed surgery. Tasting northern plums for the first time ever, I was blown away by the rich flavor. Fortunately she had too many and insisted I take 50 pounds home with me!
What appear to be Pembina plums. We canned these in syrup and ate as many as we could fresh. Photo 6.
Well, I determined right then, I needed to find out more about her trees. She had forgotten what varieties she had planted, but the trees came from retail nurseries that resold wholesale trees about 15 years previous. I took pictures, and examined leaves, fruit, buds and flowers. Using the Trees of Canada field guide and info from the U of S website among others, I have been identifying the trees based on revealed characteristics that are unique to each.
We are certain that one is a Canada Plum Prunus nigra, the essential pollinator of hybrid plums. The leaves, and fruit match up. The flowers are small , white turning pinkish with time, never suckering from the roots. It is naturally semi dwarf in this climate. Linda planted this Plum, realizing after planting the first Plum that she needed a pollinator. Fortunately the nursery sold her the right tree.
Prunus nigra. Canada Plum Spring 2017. Linda's garden. Photo 7.
Prunus Nigra Canada Plum a wonderful Plum with a tart apricot flavor. Made excellent jam. August 2016. Photo 8.
Judging by the fruit, and the general availability of hybrid Plum varieties in mainstream nurseries, the biggest tree seemed closest to the description and photos of Pembina. One characteristic of this tree was that root suckers were profuse. I was given permission to dig as many as I wished. I now have ten of them growing in pots and the ground.
Linda and I assumed that the suckers were from Pembina Plum. This spring I made sure to observe the flowers closely. The Canada Plum had flowers that matched the ID keys perfectly. The Pembina had large white blossoms but the rootsuckers had formed a shrublike tree nearby that was now covered in blossoms for the first time. Small white blossoms with no pink. No fruit has yet been observed on the small tree. Maybe this year we will see some fruit and be able to be more certain of its identity. So the suckers are not Pembina but it's grafted rootstock. There are only so many species of hardy Plum that can be used as rootstock. The profuse suckering, flowers, and leaf shape are matching up with Prunus Americana and I have used it as rootstock for my Plum scions, Too early to know yet just how many grafts will take. I am hoping for at least 50 percent success. It would seem best to avoid making too many assumptions here but close observation will continue and I am certain in time the truth will be revealed.
Left : Pembina blossoms, middle: Canada Plum with pink sepals, Right: possibly Prunus Americana American Wild Plum. Photo 9.
What seems to be Prunus Americana in Linda's garden Photo 10.
DBG Fruit Growers’ Bulletin 1-17 added May 24, 2017
Apple Maggots By Thean Pheh May 24, 2017
In spite all the advancement in technology weather is still the most effective controlling agent for pests and diseases. She had given us a helping hand in 2015 and 2016 in reducing the Apple Maggot population. (Over a hundred adults used to get caught on the yellow sticky traps I set up for monitoring. In 2015 and 2016 there were less than 20.) The spring of those two years were either too dry or wet and cold. Last winter we experienced an interesting winter. The snow came late and there was not as much when compared to other years. We also experienced a yoyo spring where it was much hotter for a week and then immediately followed by much colder temperatures for a week or so throughout March and April. I noticed stagnant pools of water in my yards during those hot periods. Hopefully this will further reduce the Apple Maggot population.
Whatever it is, don’t be over confident: continue to monitor and take proactive measures. GF 120 has a pre-harvest interval of just one day and CFIA has approved it as an organic insecticide for controlling Apple Maggots. Unfortunately it is not available in Alberta. (It’s available in BC. Yes, Apple Maggots have reached BC.) Many of us use barriers to deny the females any access to the fruits. Self-locking plastic bags were the standard most of us were using. Nylon bags designed for bagging fruits are now sold in some stores in Canada. I believe they are sold as orchard sox. (Sorry, I have not done my annual rounds of local nurseries and garden centres to see if this nylon bags are available locally.)
For those of us diehards who still want to use plastic bags. Those who are planning to start using this method, here are some tips. I prefer to use those with color locking mechanisms. The change in color when locking is properly done is reassuring. Secondly the bags also last longer. (Most lasted three years for me.) I cut the bottom corners off at 45o angle, resulting in about an inch cut. This is very important as the cuts allow hot air to escape and water to drain out. I use 65/8 x 57/8 inch sandwich bags. This size will accommodate apples up to 3” in diameter. In my nick of the woods, I found the adults do not emerge until end of June. They spend 2 weeks looking for food before laying their eggs. To err on the side of caution I always had all the bagging done by the first 7 days of July. Shannon bags hers much earlier. (Refer to Shannon’s article in earlier Bulletin.)
Unknown
The much colder season last year with periods of rain and drought wreck havoc for many of us last year. Many apples develop bitter pit. The characteristic symptom of bitter pit is dried dark spots inside the meat. In my case there were many situations where the dark spots were not caused by the ‘disease’. (Bitter pit is not a pathogenic disease but a physiological disorder.) I could trace the spots to minute punctures on the skin. Although not certain I firmly believe they were caused by some sucking insects, most likely a stinkbug. I just hope and pray Alberta Agriculture is correct in that the Brown Marmorated Stink Bug (BMSB) is not found in Alberta. But then who knows as one found in Balzac in 2008. (Also bear in mind Alberta Agriculture still denies the existence of the Black Currant Weevil when I know it is wreaking more damages to gooseberries and currants than the Current Fruit Flies from Central to Southern Alberta. It is also wrecking various cherries.) From last year’s observations I noticed those bagged apples with bitter pith did not have any puncture holes on those skin. From this I am cautiously optimistic that bagging may help in preventing any stink bug’s damages. However I may have to follow Shannon and begin to bag earlier since stink bug overwinters as adult.
Winter Hardiness
Some of you know that I have been growing fruit trees in containers. I cannot call it Penjing or Bonsai as I do not adhere to their strict principles of container selection, training and other cultural regimes. Anyway I have been at it for over 2 decades and had few problems over-wintering every plant outdoors. However with less snow and the yoyo spring this year is brutal: I lost many plants - apples, Nanking cherries, hawthorn, blueberries and plums. The silver lining to this experience is it did provide me some insights into which rootstocks to use in future. If you are interested in growing fruit trees in containers don’t hesitate to drop me a line.
Footnote
Thank you, Gabe, for suggesting and encouraging me to write this piece.
Whatever it is, don’t be over confident: continue to monitor and take proactive measures. GF 120 has a pre-harvest interval of just one day and CFIA has approved it as an organic insecticide for controlling Apple Maggots. Unfortunately it is not available in Alberta. (It’s available in BC. Yes, Apple Maggots have reached BC.) Many of us use barriers to deny the females any access to the fruits. Self-locking plastic bags were the standard most of us were using. Nylon bags designed for bagging fruits are now sold in some stores in Canada. I believe they are sold as orchard sox. (Sorry, I have not done my annual rounds of local nurseries and garden centres to see if this nylon bags are available locally.)
For those of us diehards who still want to use plastic bags. Those who are planning to start using this method, here are some tips. I prefer to use those with color locking mechanisms. The change in color when locking is properly done is reassuring. Secondly the bags also last longer. (Most lasted three years for me.) I cut the bottom corners off at 45o angle, resulting in about an inch cut. This is very important as the cuts allow hot air to escape and water to drain out. I use 65/8 x 57/8 inch sandwich bags. This size will accommodate apples up to 3” in diameter. In my nick of the woods, I found the adults do not emerge until end of June. They spend 2 weeks looking for food before laying their eggs. To err on the side of caution I always had all the bagging done by the first 7 days of July. Shannon bags hers much earlier. (Refer to Shannon’s article in earlier Bulletin.)
Unknown
The much colder season last year with periods of rain and drought wreck havoc for many of us last year. Many apples develop bitter pit. The characteristic symptom of bitter pit is dried dark spots inside the meat. In my case there were many situations where the dark spots were not caused by the ‘disease’. (Bitter pit is not a pathogenic disease but a physiological disorder.) I could trace the spots to minute punctures on the skin. Although not certain I firmly believe they were caused by some sucking insects, most likely a stinkbug. I just hope and pray Alberta Agriculture is correct in that the Brown Marmorated Stink Bug (BMSB) is not found in Alberta. But then who knows as one found in Balzac in 2008. (Also bear in mind Alberta Agriculture still denies the existence of the Black Currant Weevil when I know it is wreaking more damages to gooseberries and currants than the Current Fruit Flies from Central to Southern Alberta. It is also wrecking various cherries.) From last year’s observations I noticed those bagged apples with bitter pith did not have any puncture holes on those skin. From this I am cautiously optimistic that bagging may help in preventing any stink bug’s damages. However I may have to follow Shannon and begin to bag earlier since stink bug overwinters as adult.
Winter Hardiness
Some of you know that I have been growing fruit trees in containers. I cannot call it Penjing or Bonsai as I do not adhere to their strict principles of container selection, training and other cultural regimes. Anyway I have been at it for over 2 decades and had few problems over-wintering every plant outdoors. However with less snow and the yoyo spring this year is brutal: I lost many plants - apples, Nanking cherries, hawthorn, blueberries and plums. The silver lining to this experience is it did provide me some insights into which rootstocks to use in future. If you are interested in growing fruit trees in containers don’t hesitate to drop me a line.
Footnote
Thank you, Gabe, for suggesting and encouraging me to write this piece.
Photos inserted by Jo for illustration purposes only.
DBG Fruit Growers’ Bulletin 3-16 added Nov. 7, 2016
2016 Fruit Show By Thean Pheh Nov. 7, 2016
The growing season for the year started about three weeks earlier than norm and on a very positive note. However, late frosts in Alberta and Saskatchewan dashed the hopes of many. I was expecting very, very few fruits at this year’s show. However I was wrong. In terms of the amount of fruits there is no question this was the poorest since the show started in 1989. But, members put in their best to put on another very educational and successful show. We can all hold our heads high and push our chest forward. I am sorry I missed the Saturday session again.
Every year I record the fruits that were brought to the show. With so many members of the public coming in earlier than usual I lost the opportunity. Each year, I look forward to the ‘below the table deal’. These were small samples, the ‘latest kid in the block’, that made the event interesting for those of us who showed up on Sunday. Normally there were just one or two but this year there were several. Among them were Temboli pear, Haganta plum, Somerset grapes, an unknown pear with excellent dessert qualities and several apples. It used to be when we could help to identify almost every apple brought in by members of the public. This year many were unidentifiable. This plus the ‘under the table deal’ solidify my belief there is a future for fruit growing on the prairie. (Ken Willis talked on this subject at the show.)
2016 was an abnormal year, especially for growers in Edmonton. Not only did spring come three weeks earlier but April and May were hotter than norm. We had 99 days when the temperature was higher than 20oC. That, according to the weatherman, is a new record. However we did not get a single day of 30oC and above. (I do not know if this is also a record.) Corn heat units for the months of July and August were lower than other years. Although we only had a couple of days with torrential rain, on average we received precipitation every 3 days out of 5. With these anomalies apples, pears and plums were certainly bigger and juicier but not as sweet and flavorful. I also noted or experienced several problems that in the past were non-existent or too insignificant to be alarmed but too prevalent this year to be ignored.
With much reduced population of apple maggot, black currant weevil and currant fruit fly, I was dreaming of an annus mirabilis. Instead it turned into annus horribilis - no apricot harvest in spite the heaviest fruiting and very few whole pears. Lapin cherry fruited for the first time but black currant weevil got all except one that was later eaten by bird. Plums were good and I was lucky to escape the several heavy hails that hit many areas but late heavy rain split most of the Japanese and some European plums. On the positive note I got bumper crops of gooseberries and currants; more than I could consume.
Apple curculios are all over my saskatoons every year but rarely touched the pears. This year it was difficult for me to find an undamaged pear. (Picture #1). The pears had to be eaten with care as there are hard stony cells at the end of each puncture point. In over 30 years since I moved into this house I have never gotten an apple defaced by apple curculio but this year many were damaged (Picture #2); some to a point where the apples could not be eaten.
In spite the earlier spring I did not notice earlier emergence of the apple maggot. Like last year I have lower apple maggot population but I still bagged the apples I wanted. I always leave a few without bags as ‘catch crop’ to encourage the adults to lay their eggs so that I can harvest the apples to destroy the maggots. In the past any catch crop of Norkent, Heyer 12 and Rescue will be heavily infested but this year I picked a few totally apple maggot free, although not unblemished by damages from an unknown pest (see last paragraph).
Even in very light cropping years I never had one ‘wormy’ apricot. This year, the heaviest crop since I started planting apricot in late 80’s, I experienced 100% infestation. Most fruits have at least two maggots. The damages are typical of the Diptera. The Dipter maggots have reduced mouthparts. So, they inject digestive juices into the fruit to digest the pulp and then slurp up the resulting wet mushy pulp; rather disgusting - swimming and eating in their food and excreta. I have reports from a few other gardeners who also have this problem. I do not know what the pest is although my gut feeling is apple maggot is the culprit. For the time being we are calling the phenomenon ‘wormy apricot’. I have collected some pupae and hopefully some will emerge in June next year for positive identification.
I think I might have another insect pest on my apple. See picture #3. Only a few apples were infested. I thought it was apple maggot and did not pay any attention until I picked the apples for grinding to get rid of the maggots. When I noticed the exit holes were too small for apple maggot I started dissecting. The larva burrows just below the skin for a distance of about 3 inches before exiting. The tunnel is very small, uniform in diameter and appears to be plugged with dried feces. Damage was confined to the tunnel itself and the flesh of the apple around the tunnel is normal and the apple is perfectly edible after peeling. I hope it’s only me who is having this problem. Have any other growers experienced this? Please let others know so that we can have a better picture. I’ll be on a lookout next year and hope to collect a few pupae to keep until they emerge.
Besides apple maggots, apple curculio, apple shoot midge, chalcid wasp, the unknown pest mentioned in the paragraph above, almost every apple and applecrab had dried pockets and stony cells. Some of them were due to bitter pit while most were caused by some sucking insects, most likely a stink bug. Bitter pit is caused by calcium deficiency. It may not be due to calcium deficiency in the soil but other factors can come into play. Among them are excess or insufficient soil moisture and the weather. I believe this year’s abnormality is moisture and weather related. Aside from the ugly dried spots and stony cells, affected apples develop a slight bitter after taste, making eating rather unpleasant; even dehydrated apples had the bitter taste. I am more worried when I think the majority is most likely caused by sucking insects. To date the most serious is the Brown Marcorated Stink Bug (BMSB), a native of Asia that sneaked into North America by hiding in shipping crates. It is causing serious damages for commercial apple growers in the States and Ontario. Almost all my apples and crabapples (over 90%) that were not bagged have the typical signs of BMSB attack. There is very little to salvage for eating as damages are distributed throughout the fruits. The insect punctured the skin (see picture #4) with its long proboscis to inject digestive enzymes before sucking up the partially digested juices that resulted in dried ‘pockets’ (see picture #5). I have an unknown variety that I have never bagged because its apples were too high and rarely attacked by apple maggot. It had over 300 apples and as expected very few had apple maggots but every single apple had dried pockets. Olds College and Alberta Agriculture set up traps for the past three years but so far no BMSB has been found in any trap. I hope their results are accurate and I am dead wrong(1). Nonetheless whether it’s BMSB or other stink bugs that are causing the damages, the suddenness and extent of damages I am experiencing should be a grave concern to all Canadians. If it is indeed BMSB, all gardeners will suffer heavy losses as it attacks a very wide range of fruits and vegetables. If you have the same problem please let us or Dr. Fry know.
Footnote.
(1) An adult BMSB was found in Balzac, Alberta in 2008.
* Although Picture #1 only shows two puncture points of the apple curculio, there were three on this Ure.
* Picture #3 reveals the tunnel after the skin was peeled. The abrupt end was the exit point.
* The variety in Picture #4 is OGT. OGT has inconspicuous white lenticels. The dark marks are not lenticels but punctured marks.
Every year I record the fruits that were brought to the show. With so many members of the public coming in earlier than usual I lost the opportunity. Each year, I look forward to the ‘below the table deal’. These were small samples, the ‘latest kid in the block’, that made the event interesting for those of us who showed up on Sunday. Normally there were just one or two but this year there were several. Among them were Temboli pear, Haganta plum, Somerset grapes, an unknown pear with excellent dessert qualities and several apples. It used to be when we could help to identify almost every apple brought in by members of the public. This year many were unidentifiable. This plus the ‘under the table deal’ solidify my belief there is a future for fruit growing on the prairie. (Ken Willis talked on this subject at the show.)
2016 was an abnormal year, especially for growers in Edmonton. Not only did spring come three weeks earlier but April and May were hotter than norm. We had 99 days when the temperature was higher than 20oC. That, according to the weatherman, is a new record. However we did not get a single day of 30oC and above. (I do not know if this is also a record.) Corn heat units for the months of July and August were lower than other years. Although we only had a couple of days with torrential rain, on average we received precipitation every 3 days out of 5. With these anomalies apples, pears and plums were certainly bigger and juicier but not as sweet and flavorful. I also noted or experienced several problems that in the past were non-existent or too insignificant to be alarmed but too prevalent this year to be ignored.
With much reduced population of apple maggot, black currant weevil and currant fruit fly, I was dreaming of an annus mirabilis. Instead it turned into annus horribilis - no apricot harvest in spite the heaviest fruiting and very few whole pears. Lapin cherry fruited for the first time but black currant weevil got all except one that was later eaten by bird. Plums were good and I was lucky to escape the several heavy hails that hit many areas but late heavy rain split most of the Japanese and some European plums. On the positive note I got bumper crops of gooseberries and currants; more than I could consume.
Apple curculios are all over my saskatoons every year but rarely touched the pears. This year it was difficult for me to find an undamaged pear. (Picture #1). The pears had to be eaten with care as there are hard stony cells at the end of each puncture point. In over 30 years since I moved into this house I have never gotten an apple defaced by apple curculio but this year many were damaged (Picture #2); some to a point where the apples could not be eaten.
In spite the earlier spring I did not notice earlier emergence of the apple maggot. Like last year I have lower apple maggot population but I still bagged the apples I wanted. I always leave a few without bags as ‘catch crop’ to encourage the adults to lay their eggs so that I can harvest the apples to destroy the maggots. In the past any catch crop of Norkent, Heyer 12 and Rescue will be heavily infested but this year I picked a few totally apple maggot free, although not unblemished by damages from an unknown pest (see last paragraph).
Even in very light cropping years I never had one ‘wormy’ apricot. This year, the heaviest crop since I started planting apricot in late 80’s, I experienced 100% infestation. Most fruits have at least two maggots. The damages are typical of the Diptera. The Dipter maggots have reduced mouthparts. So, they inject digestive juices into the fruit to digest the pulp and then slurp up the resulting wet mushy pulp; rather disgusting - swimming and eating in their food and excreta. I have reports from a few other gardeners who also have this problem. I do not know what the pest is although my gut feeling is apple maggot is the culprit. For the time being we are calling the phenomenon ‘wormy apricot’. I have collected some pupae and hopefully some will emerge in June next year for positive identification.
I think I might have another insect pest on my apple. See picture #3. Only a few apples were infested. I thought it was apple maggot and did not pay any attention until I picked the apples for grinding to get rid of the maggots. When I noticed the exit holes were too small for apple maggot I started dissecting. The larva burrows just below the skin for a distance of about 3 inches before exiting. The tunnel is very small, uniform in diameter and appears to be plugged with dried feces. Damage was confined to the tunnel itself and the flesh of the apple around the tunnel is normal and the apple is perfectly edible after peeling. I hope it’s only me who is having this problem. Have any other growers experienced this? Please let others know so that we can have a better picture. I’ll be on a lookout next year and hope to collect a few pupae to keep until they emerge.
Besides apple maggots, apple curculio, apple shoot midge, chalcid wasp, the unknown pest mentioned in the paragraph above, almost every apple and applecrab had dried pockets and stony cells. Some of them were due to bitter pit while most were caused by some sucking insects, most likely a stink bug. Bitter pit is caused by calcium deficiency. It may not be due to calcium deficiency in the soil but other factors can come into play. Among them are excess or insufficient soil moisture and the weather. I believe this year’s abnormality is moisture and weather related. Aside from the ugly dried spots and stony cells, affected apples develop a slight bitter after taste, making eating rather unpleasant; even dehydrated apples had the bitter taste. I am more worried when I think the majority is most likely caused by sucking insects. To date the most serious is the Brown Marcorated Stink Bug (BMSB), a native of Asia that sneaked into North America by hiding in shipping crates. It is causing serious damages for commercial apple growers in the States and Ontario. Almost all my apples and crabapples (over 90%) that were not bagged have the typical signs of BMSB attack. There is very little to salvage for eating as damages are distributed throughout the fruits. The insect punctured the skin (see picture #4) with its long proboscis to inject digestive enzymes before sucking up the partially digested juices that resulted in dried ‘pockets’ (see picture #5). I have an unknown variety that I have never bagged because its apples were too high and rarely attacked by apple maggot. It had over 300 apples and as expected very few had apple maggots but every single apple had dried pockets. Olds College and Alberta Agriculture set up traps for the past three years but so far no BMSB has been found in any trap. I hope their results are accurate and I am dead wrong(1). Nonetheless whether it’s BMSB or other stink bugs that are causing the damages, the suddenness and extent of damages I am experiencing should be a grave concern to all Canadians. If it is indeed BMSB, all gardeners will suffer heavy losses as it attacks a very wide range of fruits and vegetables. If you have the same problem please let us or Dr. Fry know.
Footnote.
(1) An adult BMSB was found in Balzac, Alberta in 2008.
* Although Picture #1 only shows two puncture points of the apple curculio, there were three on this Ure.
* Picture #3 reveals the tunnel after the skin was peeled. The abrupt end was the exit point.
* The variety in Picture #4 is OGT. OGT has inconspicuous white lenticels. The dark marks are not lenticels but punctured marks.
Summary in Grafting Compatibility-supplied by Gabe Botar
Summary of info gathered in Grafting Laboratory, Pl.Sc. 335.
- Know your plant material ! This will guide you in choosing compatible stocks and scions, and give you greater control over the final size, shape and makeup of your grafted plant .
- Safety above all !!! Use appropriate tools. Your grafting/budding knife must be razor-sharp, rigid and unbreakable. When tying/sealing the graft area, be aware that in order to prevent girdling you may eventually need to cut the cloth tape, raffia, etc. used to hold the stock and scion together. (Softer materials such as rubber budding strips, parafilm, and masking tape will usually degrade and fall off on their own, without needing to be cut. Vinyl tape and rubber/silicone tape will probably need monitoring/cutting to prevent girdling.)
- Evergreen tropical plants and greenhouse ornamentals can usually be grafted in any season, but spring is usually best since daylength is increasing then. Monocots cannot be grafted.
- In the Edmonton area, observe the following rules of thumb for fruit trees (apples, pears, plums, cherries) :
. Collect dormant scionwood/budsticks in late February/early March ; store with a moist (not wet !) paper towel in a sealed plastic bag in the refrigerator, at 2-4C. ((Scions may last for months if kept this way at 2C…and for a week or so if kept at 10C.)
. Graft or bud after May 1. The best time is about mid-May. At this point the sap is rising in the stock but the scions should still be dormant. If you can keep a scion dormant, it may be grafted successfully onto a suitable rootstock as late as July, and still make growth and harden off in time for the coming winter. All the grafts will work this way, as will chip & Jones buds.
. The first week in August is usually the “window” for doing T-buds, because the stock bark is “slipping” then. Whereas the scionwood/ budsticks used around May 1 and later have no foliage, T-buds will have leaves at the nodes. (Remove the leaf blades but keep the petioles, which are good little handles ; after the budding procedure, the petioles should fall off after 10 days or so.) On the budstick, avoid basal and terminal buds, choosing the plump and mature medial buds of the current season’s growth. Jones and chip buds do not need to have the stock bark "slipping" and have a wider latitude for budding time. - Be clear about the difference between TOPWORKING and FRAMEWORKING, and the advantages of each.
- Some compatibility hints :
. A species is usually graft-compatible on its own seedlings ; thus, an apple will usually graft successfully onto an apple, etc. In our climate, just about any Malus scion will graft onto the same or another Malus cultivar or species. Crabapples and large-fruited apples can be grafted onto each other, but be aware of what can happen when stocks and scions with very different growth rates and growth habits are combined.
. Graft plums and cherry-plum hybrids onto most plums, sandcherry, or nanking cherry.
. Graft hardy apricots onto sandcherry, but not onto nanking cherry or plum (some salicinas excepted), unless you want to hold the scion for only a couple of seasons or less before final grafting onto a sandcherry. Apricots on sandcherry need to be staked. If you use sandcherry as an interstem, apricots will usually do well on plums and nanking cherries.
. Graft pears onto saskatoons and cotoneasters and some hawthorns (especially Japanese) and mountain ash. Note the need to keep some of the original foliage below the graft on saskatoons and cotoneasters. Compatible mountain ash rootstocks do not have this requirement and usually do not need staking. If using seedlings for pear rootstocks, use seeds from hybrid hardy pears rather than seeds from pure Ussurian pear lines.
. Graft saskatoons onto cotoneaster (usually successful) or compatible mountain ash. If the compatibility with the mountain ash is unknown, try a cotoneaster interstem.
. Graft sour cherry onto mongolian cherry or pincherry (or hardy sweet cherry in relatively warm microclimates). Seedlings of the sour cherry 'Evans' are usually compatible stocks for sweet and sour cherries here but often short-lived. Alternatively, sweet and sour cherries can usually be grafted onto Amur cherry or Amur cherry interstems on mayday. The hardiest sweet cherries in our area usually graft well onto 'Evans' sour cherry. The true (sweet and sour) cherries are usually not compatible on sandcherry or nanking cherry, which are more closely related to plums.
. Graft chokecherry onto amur cherry, or mayday (usually, but not always; consider using an Amur cherry interstem on maydays). (Chokecherries are not compatible with the true cherries in f. above).
. Graft red and white currants and gooseberries onto Ribes aureum or its close relatives (usually successful) ; the resulting plants are taller, more productive, and easier to harvest).
. Common (French) lilacs (Syringa vulgaris) often sucker badly. They can be grafted successfully onto non-suckering late lilacs (Syringa villosa) only if an interstem of dwarf Korean lilac (Syringa meyeri) is used.
DBG Fruit Growers’ Bulletin 2-16 added March 27, 2016
Viva Pomona: Experimenting with Fruit Wine By Shannon Campbell March 12, 2016
Introduction
Few home-garden fruit growers would dispute the fact that Alberta fruits tend to arrive in a glut. What does one do, after you have extracted the juice, baked the pies, made the preserves and gifted a good variety of the surplus to discerning recipients? Although the products are all superior to commercial sources, it is difficult to compete with a food industry which can put juice on the supermarket shelves at $1 a litre.
Wine came to mind as a way to use the surplus. Some growers had been making their own for years. There were a number of commercial establishments producing fruit wine, but they could not make use of random supplies. Somewhere on the continuum between the growers and the wineries, there had to be another group who were somewhat experienced in winemaking (at least from kits), interested in a little challenge and could see beyond the grape.
About ten years ago, contemplating another season's bounty, a number of us decided to put our various skills--sourcing, collecting, juicing and winemaking-- together to test the theory.
Challenges
There were several hurdles to clear.
1. Variable Juice Supply: Supply was unpredictable, both in amount and apple variety, depending on such factors as the growing season and which tree owners were keen to have their fruit collected.
2. Storage: Fruit wine was considered to decline in quality in storage.
3. Processing and disposal of Waste: Juicing of small amounts of fruit is a time-consuming process. Disposing of pomace and waste from the process is easier if you have a handy flock of sheep or other stock animals but not everyone has such a resource.
4. Experience among winemakers: While there are multiple resources on-line implying that making apple wine is as easy as making apple pie, experience counts when handling raw juice with variable balances of sugars and acids.
Obtaining Fruit
Wayne Fuhr led a group of "finders-and-pickers". Pails of fruit would appear at intervals. He would be pleased with a new source and occasionally a bit downcast, if philosophical, when a splendid Heyer 12, or some such tree, was cut down. Sometimes we wound up balancing on precarious supports to pick fruit from (now well-grown) trees he had given one or another friend many years before. Donors of fruit would receive bottles of wine later in the season to encourage them to keep their trees, or--even better--make their own wine.
Preparing Juice
Using a home juicer (without heat), I washed, trimmed and juiced....one apple at a time. This was an excessively messy job, best done in the back garden to avoid having juice and bits of apple on every flat surface in the kitchen. Wasps were a nuisance, trying to drown happily in the juice. Evans cherries, grapes and chokecherries got a straightforward picking-over, washing and a short period of freezing to release the juice. Darvin Krysko, the winemaker, received the raw apple juice in 25 litre batches, the cherries in 10-15 kg lots and the Valiant grapes and wild chokecherries in whatever quantity was available. The sheep got the pomace and trimmings, making a short and thorough job of devouring whatever landed in their trough.
Developing the Product
We chose the name "Viva Pomona". Over the decade, we experimented with single-variety juice (a method promoted by Robert Mondavi for new world wines), multiple-variety blends (used by London Glider Ciders) and seasonal blends. Blends were made with no less than three different apples and frequently more, depending on what was available. Fruits ranged from large to small; from early Heyer 12 through late-fall Hibernal. No cider apples were included, only because none were ever located. Cherry wine was made straight or variously blended with apple, grape and chokecherry juices. Darv produced sweet wine, dry wine and even some dessert wine.
The apple maggot became an increasingly problematic pest. More fruit had to be rejected. If the damage was minor, it still required considerable trimming and increased the amount of waste. No bruised or damaged material went into the juicer, in order to ensure only the highest quality input to the process.
What did we learn?
1. Variability: The random nature of the fruit supply did not affect the quality of the final product.
Blended juices provided more complex flavours, compared to juice from a single variety. This applied to both apple and cherry.
Early season apple wine resulted in a light, fresh, citrusy taste while late season had a more golden mellow flavour. Mid-season product varied, depending on what types of apples were available.
2. Storage: In a cool, dark storage place, early bottles have retained their good characteristics.
3. Processing and waste disposal: Raw juice has to be produced and moved quickly to the winemaker as natural fermentation will soon start. (I did not use any product to sterilize the juice but some lots were frozen for a few days before there was capacity in the wine-making department.) The inefficiency of production and waste disposal could be minimized by producing blended juices in 25 litre quantities (or smaller amounts for those wishing partial batches) in a single location, preferably with a friendly farmer nearby.
4. Experience: This experiment has demonstrated that home winemakers who have experience at the level of using wine kits can consistently produce an excellent product from juices of local fruits.
Conclusion
"Viva Pomona" wines proved to be successful every year. They were pleasant to sip on their own or with meals. Apple wines were best served a little cool, while cherry wines developed more flavour when taken out of the cellar 20 minutes before serving. The flavour was rich and smooth, without harshness or other negative characteristics.
The decade-long Viva Pomona experiment has now been concluded. Having tested the theory (and the product) extensively, we now encourage others to consider further opportunities for converting local juice to wine.
Few home-garden fruit growers would dispute the fact that Alberta fruits tend to arrive in a glut. What does one do, after you have extracted the juice, baked the pies, made the preserves and gifted a good variety of the surplus to discerning recipients? Although the products are all superior to commercial sources, it is difficult to compete with a food industry which can put juice on the supermarket shelves at $1 a litre.
Wine came to mind as a way to use the surplus. Some growers had been making their own for years. There were a number of commercial establishments producing fruit wine, but they could not make use of random supplies. Somewhere on the continuum between the growers and the wineries, there had to be another group who were somewhat experienced in winemaking (at least from kits), interested in a little challenge and could see beyond the grape.
About ten years ago, contemplating another season's bounty, a number of us decided to put our various skills--sourcing, collecting, juicing and winemaking-- together to test the theory.
Challenges
There were several hurdles to clear.
1. Variable Juice Supply: Supply was unpredictable, both in amount and apple variety, depending on such factors as the growing season and which tree owners were keen to have their fruit collected.
2. Storage: Fruit wine was considered to decline in quality in storage.
3. Processing and disposal of Waste: Juicing of small amounts of fruit is a time-consuming process. Disposing of pomace and waste from the process is easier if you have a handy flock of sheep or other stock animals but not everyone has such a resource.
4. Experience among winemakers: While there are multiple resources on-line implying that making apple wine is as easy as making apple pie, experience counts when handling raw juice with variable balances of sugars and acids.
Obtaining Fruit
Wayne Fuhr led a group of "finders-and-pickers". Pails of fruit would appear at intervals. He would be pleased with a new source and occasionally a bit downcast, if philosophical, when a splendid Heyer 12, or some such tree, was cut down. Sometimes we wound up balancing on precarious supports to pick fruit from (now well-grown) trees he had given one or another friend many years before. Donors of fruit would receive bottles of wine later in the season to encourage them to keep their trees, or--even better--make their own wine.
Preparing Juice
Using a home juicer (without heat), I washed, trimmed and juiced....one apple at a time. This was an excessively messy job, best done in the back garden to avoid having juice and bits of apple on every flat surface in the kitchen. Wasps were a nuisance, trying to drown happily in the juice. Evans cherries, grapes and chokecherries got a straightforward picking-over, washing and a short period of freezing to release the juice. Darvin Krysko, the winemaker, received the raw apple juice in 25 litre batches, the cherries in 10-15 kg lots and the Valiant grapes and wild chokecherries in whatever quantity was available. The sheep got the pomace and trimmings, making a short and thorough job of devouring whatever landed in their trough.
Developing the Product
We chose the name "Viva Pomona". Over the decade, we experimented with single-variety juice (a method promoted by Robert Mondavi for new world wines), multiple-variety blends (used by London Glider Ciders) and seasonal blends. Blends were made with no less than three different apples and frequently more, depending on what was available. Fruits ranged from large to small; from early Heyer 12 through late-fall Hibernal. No cider apples were included, only because none were ever located. Cherry wine was made straight or variously blended with apple, grape and chokecherry juices. Darv produced sweet wine, dry wine and even some dessert wine.
The apple maggot became an increasingly problematic pest. More fruit had to be rejected. If the damage was minor, it still required considerable trimming and increased the amount of waste. No bruised or damaged material went into the juicer, in order to ensure only the highest quality input to the process.
What did we learn?
1. Variability: The random nature of the fruit supply did not affect the quality of the final product.
Blended juices provided more complex flavours, compared to juice from a single variety. This applied to both apple and cherry.
Early season apple wine resulted in a light, fresh, citrusy taste while late season had a more golden mellow flavour. Mid-season product varied, depending on what types of apples were available.
2. Storage: In a cool, dark storage place, early bottles have retained their good characteristics.
3. Processing and waste disposal: Raw juice has to be produced and moved quickly to the winemaker as natural fermentation will soon start. (I did not use any product to sterilize the juice but some lots were frozen for a few days before there was capacity in the wine-making department.) The inefficiency of production and waste disposal could be minimized by producing blended juices in 25 litre quantities (or smaller amounts for those wishing partial batches) in a single location, preferably with a friendly farmer nearby.
4. Experience: This experiment has demonstrated that home winemakers who have experience at the level of using wine kits can consistently produce an excellent product from juices of local fruits.
Conclusion
"Viva Pomona" wines proved to be successful every year. They were pleasant to sip on their own or with meals. Apple wines were best served a little cool, while cherry wines developed more flavour when taken out of the cellar 20 minutes before serving. The flavour was rich and smooth, without harshness or other negative characteristics.
The decade-long Viva Pomona experiment has now been concluded. Having tested the theory (and the product) extensively, we now encourage others to consider further opportunities for converting local juice to wine.
Rootstocks By Thean Pheh March 27, 2016
In the spring issue of 2014 we briefly touch on the various rootstocks for various crops. In this issue let’s look into it in greater depth.
Essentially the aim of budding and grafting is the same - joining two different plants together. While budding uses a single bud, a short piece of stem is used in grafting. The bottom half is known as rootstock while the top is called the scion or top-work. Purely for ease of operation and cost effectiveness almost all such trees sold in nurseries are budded but for unknown reasons they are always referred to grafted trees. As such for this treatise, whether budded or grafted we shall refer to the operation as grafting.
For gardeners it is not good enough to unite two trees together. It is crucial they must be able to grow and produce as one for a long time. Since they have different genome even the most compatible have some ‘disagreements’. Actually the correct technical term is incompatibility but ‘disagreements’ sounds more dramatic and illustrative (at least in my simple brain). Like a marriage while one and one’s partner remains unchanged, each has an influence on the other’s actions and behavior. Similarly, while each part of the grafted tree retains its entire genetic makeup, each has a certain amount of influence on the other. Some of the obvious influences of value to growers are true to type, tree size, precociousness, productivity, pest and disease tolerance and winter hardiness.
True to type
Before people bite into a fruit they already have a preconceived idea of how it should taste. In an age where uniformity and consistency is demanded, having fruits that fall short of expectation is unacceptable. Since seeds are the results of random combination of genes they do not produce true to type trees. For this reason we select and propagate only those trees that produce fruits that fit our expectations. Asexual propagation was developed to propagate trees thus selected. When propagated asexually the selection becomes known as a clone. Stem cutting is the easiest, fastest and cheapest asexual method. However, some trees are extremely difficult if not impossible to propagate via cuttings. Grafting is the easiest and best method to propagate such clones.
Dwarfing
Among the most well known and sought-after result of grafting is its effect on tree size. Some dwarfs the top-work tremendously while others grow to almost normal size. A good example is apple grafted onto M27 will only grows to about 1/10 its potential size while one grafted onto open pollinated seedlings may grow to full size. Often even the growth habit can be slightly altered. M9 is the most popular and widely used dwarfing rootstock used by commercial apple producers around the globe. Besides M9 and its derivative MM9, EM9 and others, many other clones with similar effects like B9, P2, Geneva 11 are also used. Unfortunately, none of these is sufficiently hardy for Alberta. From field tests done, only Ottawa 3, more commonly known as O3, has been proven hardy to Zone 3 if there is consistent snow cover. (I have no problem with O3 in metropolitan Edmonton.) O3 is described as semi-dwarfing, about the size of M26.
Another method to obtain dwarfing effect is inter-species grafting, grafting onto a different species. Many of us are doing this effectively, for example grafting plums onto Nanking cherries or sandcherries. Many of us are doing this with apples too. On the prairie, crabapple, Malus baccata, is the most widely used rootstock for apples, Malus domestica. Unfortunately there is no dwarfing effect.
Wayne, Bernie and Evelyn had talked about grafting pears onto saskatoons and cotoneasters in previous issues. This is called inter-genus grafting. There is most ‘disagreements’ in inter-genus grafting, resulting in delayed incompatibility. Since grafting involves two individuals there must be mutual supports; ‘you feed me, I feed you’ type of scenario. Except for some pears grafted onto selected quince, in almost all cases inter-genus grafting ends up in a one way affair. More often than not it’s the rootstock that’s on the short end. With little or no feedback from the scion, the rootstock gets weaker and weaker and eventually dies. That explains why it is crucial to maintain nurse branches on the rootstocks. Generally inter-genus grafts tend to be very dwarfing. Gabe has done quite a bit of inter-genus grafting and is our best source of information.
If grafts are compatible the top-works should live for a very long time. However, most literature notes grafts on dwarfing rootstocks have a shorter lifespan. Commercial producers only expect to get 25 years out of dwarf apple trees. Personally I think this has more to do with productivity and cost of production than the state of the trees.
Precociousness
Tree fruits grown from seeds have a very long juvenile stage. Most apples take about 10 years from germination to produce the first fruits in Alberta. (I have a tree that took 27 years.) Top-work of a grafted tree retains the matured stage right from the beginning. But, it takes a couple of years to start fruiting because the top-work requires some time to build up its scaffolds and food reserves. Depending on the clones of the top-work and the rootstock, in Alberta it may take anywhere from 3 to 7 years. As a rule of thumb, top-work on dwarfing rootstock fruits much earlier. Precocious is a word often found in reports and literature. This word refers to the short period it takes for grafts to come into first fruiting. Once I had a Mantet grafted onto M9 that was plastered with flowers on a single stem 3 feet whip one year after grafting. Now that’s very precocious.
Besides the genetics of the rootstock, training and pruning has a big influence on the juvenile stage of a grafted tree. Pruning, especially severe heading back during dormant pruning, delays fruiting. The trend among commercial producers is to avoid pruning but do more training such as bending laterals to a more horizontal position to promote floral initiation.
Productivity
Productivity here refers to total volume, fruit size and culinary and eating qualities of the fruits produced. Research works showed different rootstock take up nutrients in different volume and combination or ratio. This partially explains differences in tree size and productivity. Personally I find dwarfing rootstocks not only bear bigger fruits but more fruits per volume of wood. I think there is no other clone that is more sensitive to rootstock than Collet. I have seen Collet that never grows bigger than Rescue while Collet on another tree produces full size apples all the time. (I believe Dr. Ieuan Evans can bear witness to this same observation.) I took scionwood of Parkland from my tree and grafted it for the neighbor directly across the back alley. Yet his tree produces apples almost three times the size of my Parkland every year for the past two decades. The irony is I thin the fruits on my trees thoroughly while he only raises his hand to harvest. While my Parkland is biannual his is an annual producer.
I have three PF51 grafted on three different rootstocks. In terms of fruit size there is not much difference. But each tree produces fruits that are so different in shape, color and taste that if I had not done the grafting myself I would have said they are three different clones. I love to hear from others on this phenomenon.
When I was working at CDCN, we had 5 Sim Red grafted onto open pollinated Columbia seedlings. They were lined out side by side. These trees were never pruned. Each of the trees was different in tree size and each produced fruits of different sizes. In spite the big differences actually I did not notice them until Don Siemens pointed that out to me on his first visit. After that I paid more attention and found it was not a once in the arm shot; each year’s production was a repeat of the last.
Walking
Anyone who has planted plums for some time will find root suckers popping up all over the lawn. Some people call this walking. Some trees, even clones or selections, are more prone to walking than others. This is Nature’s way of multiplication and colonization. However, this is not tolerated in home or commercial gardens. These are removed as they appear. Using non-suckering rootstock circumvent the problem.
Winter hardiness
Many literatures cite better winter hardiness as one of the reasons for grafting but they did not explain how. Cytokines, the hormone that stimulate buds and shoots to elongate, are mostly produced by the roots. As such roots have a great bearing on when the plants begins to move in spring and to shut down in fall to begin the process of acclimatization for the winter. I read somewhere in double grafting, the length of the interstock determines the efficacy of the graft. If my memory serves me right a minimum of 6 inches is required. Does this apply to regular grafting? I don’t know and would love to hear and learn from you. Most of us follow the standard recommendation of grafting 4 inches above the soil. Will grafting higher has more benefits? In terms of winter hardiness frame working has maximum effect.
Support
The greatest deficiency of dwarfing rootstock is the root systems; they either have fewer roots or the roots are brittle hence poor anchorage. Since Alberta is a windy country, all fruit trees grafted onto dwarfing rootstock must be supported for life.
This and That
* This winter proves to be the warmest; in the city there were only two nights when the mercury dipped below minus 20C. Even then it was not close to that magic figure of minus 29C when most apricot floral buds get killed. If there is no late frost from the balloon stage onwards, there should be bumper crops of apricot this year.
* Those interested in columnar apple trees might be interested in the Northern Arrow series from the University of Saskatchewan (UofS). TreasuRed, the first one to be released has been in the market for the last two years.
* The Boreal series is the latest haskap from UofS. New for 2016 is Boreal Blizzard. Look out for more releases to come.
Essentially the aim of budding and grafting is the same - joining two different plants together. While budding uses a single bud, a short piece of stem is used in grafting. The bottom half is known as rootstock while the top is called the scion or top-work. Purely for ease of operation and cost effectiveness almost all such trees sold in nurseries are budded but for unknown reasons they are always referred to grafted trees. As such for this treatise, whether budded or grafted we shall refer to the operation as grafting.
For gardeners it is not good enough to unite two trees together. It is crucial they must be able to grow and produce as one for a long time. Since they have different genome even the most compatible have some ‘disagreements’. Actually the correct technical term is incompatibility but ‘disagreements’ sounds more dramatic and illustrative (at least in my simple brain). Like a marriage while one and one’s partner remains unchanged, each has an influence on the other’s actions and behavior. Similarly, while each part of the grafted tree retains its entire genetic makeup, each has a certain amount of influence on the other. Some of the obvious influences of value to growers are true to type, tree size, precociousness, productivity, pest and disease tolerance and winter hardiness.
True to type
Before people bite into a fruit they already have a preconceived idea of how it should taste. In an age where uniformity and consistency is demanded, having fruits that fall short of expectation is unacceptable. Since seeds are the results of random combination of genes they do not produce true to type trees. For this reason we select and propagate only those trees that produce fruits that fit our expectations. Asexual propagation was developed to propagate trees thus selected. When propagated asexually the selection becomes known as a clone. Stem cutting is the easiest, fastest and cheapest asexual method. However, some trees are extremely difficult if not impossible to propagate via cuttings. Grafting is the easiest and best method to propagate such clones.
Dwarfing
Among the most well known and sought-after result of grafting is its effect on tree size. Some dwarfs the top-work tremendously while others grow to almost normal size. A good example is apple grafted onto M27 will only grows to about 1/10 its potential size while one grafted onto open pollinated seedlings may grow to full size. Often even the growth habit can be slightly altered. M9 is the most popular and widely used dwarfing rootstock used by commercial apple producers around the globe. Besides M9 and its derivative MM9, EM9 and others, many other clones with similar effects like B9, P2, Geneva 11 are also used. Unfortunately, none of these is sufficiently hardy for Alberta. From field tests done, only Ottawa 3, more commonly known as O3, has been proven hardy to Zone 3 if there is consistent snow cover. (I have no problem with O3 in metropolitan Edmonton.) O3 is described as semi-dwarfing, about the size of M26.
Another method to obtain dwarfing effect is inter-species grafting, grafting onto a different species. Many of us are doing this effectively, for example grafting plums onto Nanking cherries or sandcherries. Many of us are doing this with apples too. On the prairie, crabapple, Malus baccata, is the most widely used rootstock for apples, Malus domestica. Unfortunately there is no dwarfing effect.
Wayne, Bernie and Evelyn had talked about grafting pears onto saskatoons and cotoneasters in previous issues. This is called inter-genus grafting. There is most ‘disagreements’ in inter-genus grafting, resulting in delayed incompatibility. Since grafting involves two individuals there must be mutual supports; ‘you feed me, I feed you’ type of scenario. Except for some pears grafted onto selected quince, in almost all cases inter-genus grafting ends up in a one way affair. More often than not it’s the rootstock that’s on the short end. With little or no feedback from the scion, the rootstock gets weaker and weaker and eventually dies. That explains why it is crucial to maintain nurse branches on the rootstocks. Generally inter-genus grafts tend to be very dwarfing. Gabe has done quite a bit of inter-genus grafting and is our best source of information.
If grafts are compatible the top-works should live for a very long time. However, most literature notes grafts on dwarfing rootstocks have a shorter lifespan. Commercial producers only expect to get 25 years out of dwarf apple trees. Personally I think this has more to do with productivity and cost of production than the state of the trees.
Precociousness
Tree fruits grown from seeds have a very long juvenile stage. Most apples take about 10 years from germination to produce the first fruits in Alberta. (I have a tree that took 27 years.) Top-work of a grafted tree retains the matured stage right from the beginning. But, it takes a couple of years to start fruiting because the top-work requires some time to build up its scaffolds and food reserves. Depending on the clones of the top-work and the rootstock, in Alberta it may take anywhere from 3 to 7 years. As a rule of thumb, top-work on dwarfing rootstock fruits much earlier. Precocious is a word often found in reports and literature. This word refers to the short period it takes for grafts to come into first fruiting. Once I had a Mantet grafted onto M9 that was plastered with flowers on a single stem 3 feet whip one year after grafting. Now that’s very precocious.
Besides the genetics of the rootstock, training and pruning has a big influence on the juvenile stage of a grafted tree. Pruning, especially severe heading back during dormant pruning, delays fruiting. The trend among commercial producers is to avoid pruning but do more training such as bending laterals to a more horizontal position to promote floral initiation.
Productivity
Productivity here refers to total volume, fruit size and culinary and eating qualities of the fruits produced. Research works showed different rootstock take up nutrients in different volume and combination or ratio. This partially explains differences in tree size and productivity. Personally I find dwarfing rootstocks not only bear bigger fruits but more fruits per volume of wood. I think there is no other clone that is more sensitive to rootstock than Collet. I have seen Collet that never grows bigger than Rescue while Collet on another tree produces full size apples all the time. (I believe Dr. Ieuan Evans can bear witness to this same observation.) I took scionwood of Parkland from my tree and grafted it for the neighbor directly across the back alley. Yet his tree produces apples almost three times the size of my Parkland every year for the past two decades. The irony is I thin the fruits on my trees thoroughly while he only raises his hand to harvest. While my Parkland is biannual his is an annual producer.
I have three PF51 grafted on three different rootstocks. In terms of fruit size there is not much difference. But each tree produces fruits that are so different in shape, color and taste that if I had not done the grafting myself I would have said they are three different clones. I love to hear from others on this phenomenon.
When I was working at CDCN, we had 5 Sim Red grafted onto open pollinated Columbia seedlings. They were lined out side by side. These trees were never pruned. Each of the trees was different in tree size and each produced fruits of different sizes. In spite the big differences actually I did not notice them until Don Siemens pointed that out to me on his first visit. After that I paid more attention and found it was not a once in the arm shot; each year’s production was a repeat of the last.
Walking
Anyone who has planted plums for some time will find root suckers popping up all over the lawn. Some people call this walking. Some trees, even clones or selections, are more prone to walking than others. This is Nature’s way of multiplication and colonization. However, this is not tolerated in home or commercial gardens. These are removed as they appear. Using non-suckering rootstock circumvent the problem.
Winter hardiness
Many literatures cite better winter hardiness as one of the reasons for grafting but they did not explain how. Cytokines, the hormone that stimulate buds and shoots to elongate, are mostly produced by the roots. As such roots have a great bearing on when the plants begins to move in spring and to shut down in fall to begin the process of acclimatization for the winter. I read somewhere in double grafting, the length of the interstock determines the efficacy of the graft. If my memory serves me right a minimum of 6 inches is required. Does this apply to regular grafting? I don’t know and would love to hear and learn from you. Most of us follow the standard recommendation of grafting 4 inches above the soil. Will grafting higher has more benefits? In terms of winter hardiness frame working has maximum effect.
Support
The greatest deficiency of dwarfing rootstock is the root systems; they either have fewer roots or the roots are brittle hence poor anchorage. Since Alberta is a windy country, all fruit trees grafted onto dwarfing rootstock must be supported for life.
This and That
* This winter proves to be the warmest; in the city there were only two nights when the mercury dipped below minus 20C. Even then it was not close to that magic figure of minus 29C when most apricot floral buds get killed. If there is no late frost from the balloon stage onwards, there should be bumper crops of apricot this year.
* Those interested in columnar apple trees might be interested in the Northern Arrow series from the University of Saskatchewan (UofS). TreasuRed, the first one to be released has been in the market for the last two years.
* The Boreal series is the latest haskap from UofS. New for 2016 is Boreal Blizzard. Look out for more releases to come.
Happy New Year and all the best for 2016
DBG Fruit Growers’ Bulletin 1-16 added Jan 7, 2016
Achieving Maximum Fruit Tree Hardiness By Bernie Nikolai
No matter where amateur fruit growers live, we always want to “push the limit” in terms of what we can grow in our climate zone. If we live in zone 3 – we want to grow zone 4 trees and even give a shot now and again at the insanity of growing a zone 5 tree! It really doesn’t matter what zone we live in. For example I have a friend in Victoria, BC, Zone 8. He’s trying to grow California Navel oranges inside an unheated greenhouse!
So what is the best way to successfully winter over our tender varieties of fruit trees? What can we do within reason to ensure our trees have the best possible chance to weather our often severe prairie Canada winters?
Most of us are well aware of the parts nutrition and water have in our trees growth. We want them to grow as much as possible in our short summers, yet at the same time we want them to go into winter being completely and totally dormant. So we basically don't water our trees from September 1 on, with the exception of one last good watering in late October or early November – just before the cold and snow. This watering has the effect of putting the roots in a “giant ice cube” for the winter which will delay leafing out in the event of an early spring.
I remember visiting Lloyd Lee’s orchard near Barrhead around 10 or so years ago. Lloyd mentioned his trees were hardier in his orchard ever since he grew grass in the rows instead of cultivating black soil. He felt the competition from the grass caused the trees to dry out more in the fall, and as a result they went into winter more hardened off.
Yet there is another factor that can have a very significant affect on fruit tree hardiness in winter, especially borderline hardy varieties, namely ‘MINOR CHANGES IN ELEVATION”. These tiny changes in elevation in our orchards, and I’m talking here of only 2-8 feet, can very significantly affect a marginal trees likelihood of survival in a test winter.
Due to the marvels of “Google Translate” I’ve been reading various Russian articles and publications on their tests and results in maximizing fruit tree hardiness in Siberia. Apparently the only other area in the world with a climate similar to the Canadian prairies is the “West Siberian Plateau”. So any information we can glean from their experiences will be very helpful to us as well.
One article in particular got my attention. It claimed there can be as much as a 10 degree Celsius difference in temperature in only about 8 feet on a very cold, still night! In other words, it can be –43C outside in one part of the orchard, and only 8 ft. away it’s only –33C or –35C.
On the surface this seems utterly impossible, yet I tested it myself, and I believe it to be true! However, the trick is to realize these are “vertical feet” not “horizontal feet”. So on the coldest, ice fog night in a test winter it could be –43C right on the surface of the snow, the very coldest area. Yet only 8 ft. straight up in the branches it’s a relatively balmy –35C.
According to the Russian article I read, on the coldest nights with no wind, the cold air sinks as it is heavier. So the very coldest air flows downhill very much like a river, and collects in the lowest areas. The very coldest temperatures are right at the level of the snow, and the temperature rises about 1 degree C for every 20 cm of vertical elevation from this point. Let’s round this off so it reads “1 degree C for every vertical foot in elevation”.
I had trouble believing this, so I tested it last winter on a cold night in my backyard. Even though I live in Edmonton, I live low down in the river valley and I’m always colder than the city proper by 3-6C on a calm, cold, winter night.
I had 3 identical “max/min” thermometers that were calibrated so they read the same temperature. I put one on my fence overnight, another I hung on a rose bush 2 ft. lower, and the third thermometer I placed right on the snow in the lowest part of my backyard.
The results were very interesting to me. The coldest overnight the “max/min” thermometer on the fence recorded was –32C. Two feet lower, the thermometer on the rose bush recorded –34C. And 2 ft. below that, on the snow line in the lowest part of my backyard, the “max/min thermometer recorded –36C!
We might be tempted to think “so what? Who cares?”....
But this information could be vital in the success or failure in wintering over marginally hardy trees. It can make the difference between a tree with no winter damage and one that is dead to the snow line come spring.
Here’s how...Lets hypothetically say a tree can take –40C before it is overcome by cold and dies to the snow line. This is fairly common with many fruit trees we grow, for example Honeycrisp apple. So in the City of Edmonton Honeycrisp survives and fruits as we no longer get –40C in the city in winter. But outside the “heat island effect” of the city we can easily record much colder temperatures by several degrees C.
Let's take my hobby orchard of 300 fruit trees south of Stony Plain for example. There is approximately an 8 ft. difference in elevation over the 2 acre orchard site. The highest ground is the north east corner and the lowest, about 8 ft. lower, is in the south west corner of the orchard. So let’s say it hits –43C in the lowest part of my orchard on a very cold, windless night during a test winter. All the Honeycrisp apple trees planted in the south west corner, the lowest elevation, will be dead come spring to the snow line with almost 100% certainty. Yet at the north east corner of my orchard, only 8 ft. higher in elevation, the lowest temperatures on that same night might be only –35C, and the Honeycrisp trees planted there survive just fine, no winter damage.
Now here is an actual “real world” example of this from my personal experience. One of the new varieties of pear I’m testing at my orchard is a variety from Jim Coutts called “Coutts 28”. I have three of these trees in 3 different parts of my hobby orchard. One tree is in the lowest south west corner and it died out totally for me. I grafted it once again, but the next winter it again totally died.
The second tree is about mid way up my orchard, about three feet higher in elevation. This tree has survived, but seems to die back by about one third of its growth each colder winter.
My third and last “Coutts 28” pear tree by chance is planted in the north east corner, the highest elevation in my orchard, which again is only about 8 ft. higher in elevation from the south west corner. This “Coutts 28” tree has been totally and completely hardy, without even the slightest bit of tip dieback after the same winters!
Another “real world” example of this elevation phenomenon at my orchard has been Spartan apple which survived and fruited for over 10 years without any winter damage! Unfortunately fireblight killed this large branch about 3 years ago, but not winterkill. Since there is no way Spartan is hardy enough to survive and fruit outside the city, at my orchard, why did it do so well? The answer I believe is this...Just by chance I topworked this Spartan to a Ranetka Cab in the highest north east part of my orchard. So when it was –43C in the lowest part of my orchard, it was probably only –34 or –35C in the highest elevation spot. Since Spartan can probably take down to around –37C when fully hardened off for the winter, it survived and fruited for me for many years.
Relatively small differences in elevation can have a HUGE effect on minimum temperatures in Alberta. A friend of mine was a weather scientist for Environment Canada for years here in Edmonton. At one time there was a temperature recording station at Fort Edmonton Park, right on the banks of the North Saskatchewan River, about as low a location as is possible in Edmonton City. He looked at the records and years ago when it was –37C at the Municipal Airport, it reached –46C at this station just a few miles away! Using Honeycrisp, Spartan, or Coutts #28 pear as examples, they would have probably all survived the winter at the Municipal Airport, yet would have certainly been totally killed if they were planted at Fort Edmonton Park, only a few miles away.
The moral of this story is always plant our most tender fruit tree varieties on our highest elevation land, even if it’s only 2 or 3 feet higher. And if you really want a tender variety to have its optimal chance at survival – topwork the variety up high, 8-10 ft. off the ground, to give it the warmest temperatures in a frigid winter. Also trees planted immediately beside a Spruce tree hedge are also protected to a degree. The Spruce trees block much of the wind, as well as absorbing some heat during the day and releasing it at night, at least to some minor degree.
So the best of luck to everyone this winter! With an El Nino winter this year, I doubt we will have any winterkill problems. But this is Alberta, and we all know another test winter will surely arrive sooner or later, so we may as well be as prepared as possible.
So what is the best way to successfully winter over our tender varieties of fruit trees? What can we do within reason to ensure our trees have the best possible chance to weather our often severe prairie Canada winters?
Most of us are well aware of the parts nutrition and water have in our trees growth. We want them to grow as much as possible in our short summers, yet at the same time we want them to go into winter being completely and totally dormant. So we basically don't water our trees from September 1 on, with the exception of one last good watering in late October or early November – just before the cold and snow. This watering has the effect of putting the roots in a “giant ice cube” for the winter which will delay leafing out in the event of an early spring.
I remember visiting Lloyd Lee’s orchard near Barrhead around 10 or so years ago. Lloyd mentioned his trees were hardier in his orchard ever since he grew grass in the rows instead of cultivating black soil. He felt the competition from the grass caused the trees to dry out more in the fall, and as a result they went into winter more hardened off.
Yet there is another factor that can have a very significant affect on fruit tree hardiness in winter, especially borderline hardy varieties, namely ‘MINOR CHANGES IN ELEVATION”. These tiny changes in elevation in our orchards, and I’m talking here of only 2-8 feet, can very significantly affect a marginal trees likelihood of survival in a test winter.
Due to the marvels of “Google Translate” I’ve been reading various Russian articles and publications on their tests and results in maximizing fruit tree hardiness in Siberia. Apparently the only other area in the world with a climate similar to the Canadian prairies is the “West Siberian Plateau”. So any information we can glean from their experiences will be very helpful to us as well.
One article in particular got my attention. It claimed there can be as much as a 10 degree Celsius difference in temperature in only about 8 feet on a very cold, still night! In other words, it can be –43C outside in one part of the orchard, and only 8 ft. away it’s only –33C or –35C.
On the surface this seems utterly impossible, yet I tested it myself, and I believe it to be true! However, the trick is to realize these are “vertical feet” not “horizontal feet”. So on the coldest, ice fog night in a test winter it could be –43C right on the surface of the snow, the very coldest area. Yet only 8 ft. straight up in the branches it’s a relatively balmy –35C.
According to the Russian article I read, on the coldest nights with no wind, the cold air sinks as it is heavier. So the very coldest air flows downhill very much like a river, and collects in the lowest areas. The very coldest temperatures are right at the level of the snow, and the temperature rises about 1 degree C for every 20 cm of vertical elevation from this point. Let’s round this off so it reads “1 degree C for every vertical foot in elevation”.
I had trouble believing this, so I tested it last winter on a cold night in my backyard. Even though I live in Edmonton, I live low down in the river valley and I’m always colder than the city proper by 3-6C on a calm, cold, winter night.
I had 3 identical “max/min” thermometers that were calibrated so they read the same temperature. I put one on my fence overnight, another I hung on a rose bush 2 ft. lower, and the third thermometer I placed right on the snow in the lowest part of my backyard.
The results were very interesting to me. The coldest overnight the “max/min” thermometer on the fence recorded was –32C. Two feet lower, the thermometer on the rose bush recorded –34C. And 2 ft. below that, on the snow line in the lowest part of my backyard, the “max/min thermometer recorded –36C!
We might be tempted to think “so what? Who cares?”....
But this information could be vital in the success or failure in wintering over marginally hardy trees. It can make the difference between a tree with no winter damage and one that is dead to the snow line come spring.
Here’s how...Lets hypothetically say a tree can take –40C before it is overcome by cold and dies to the snow line. This is fairly common with many fruit trees we grow, for example Honeycrisp apple. So in the City of Edmonton Honeycrisp survives and fruits as we no longer get –40C in the city in winter. But outside the “heat island effect” of the city we can easily record much colder temperatures by several degrees C.
Let's take my hobby orchard of 300 fruit trees south of Stony Plain for example. There is approximately an 8 ft. difference in elevation over the 2 acre orchard site. The highest ground is the north east corner and the lowest, about 8 ft. lower, is in the south west corner of the orchard. So let’s say it hits –43C in the lowest part of my orchard on a very cold, windless night during a test winter. All the Honeycrisp apple trees planted in the south west corner, the lowest elevation, will be dead come spring to the snow line with almost 100% certainty. Yet at the north east corner of my orchard, only 8 ft. higher in elevation, the lowest temperatures on that same night might be only –35C, and the Honeycrisp trees planted there survive just fine, no winter damage.
Now here is an actual “real world” example of this from my personal experience. One of the new varieties of pear I’m testing at my orchard is a variety from Jim Coutts called “Coutts 28”. I have three of these trees in 3 different parts of my hobby orchard. One tree is in the lowest south west corner and it died out totally for me. I grafted it once again, but the next winter it again totally died.
The second tree is about mid way up my orchard, about three feet higher in elevation. This tree has survived, but seems to die back by about one third of its growth each colder winter.
My third and last “Coutts 28” pear tree by chance is planted in the north east corner, the highest elevation in my orchard, which again is only about 8 ft. higher in elevation from the south west corner. This “Coutts 28” tree has been totally and completely hardy, without even the slightest bit of tip dieback after the same winters!
Another “real world” example of this elevation phenomenon at my orchard has been Spartan apple which survived and fruited for over 10 years without any winter damage! Unfortunately fireblight killed this large branch about 3 years ago, but not winterkill. Since there is no way Spartan is hardy enough to survive and fruit outside the city, at my orchard, why did it do so well? The answer I believe is this...Just by chance I topworked this Spartan to a Ranetka Cab in the highest north east part of my orchard. So when it was –43C in the lowest part of my orchard, it was probably only –34 or –35C in the highest elevation spot. Since Spartan can probably take down to around –37C when fully hardened off for the winter, it survived and fruited for me for many years.
Relatively small differences in elevation can have a HUGE effect on minimum temperatures in Alberta. A friend of mine was a weather scientist for Environment Canada for years here in Edmonton. At one time there was a temperature recording station at Fort Edmonton Park, right on the banks of the North Saskatchewan River, about as low a location as is possible in Edmonton City. He looked at the records and years ago when it was –37C at the Municipal Airport, it reached –46C at this station just a few miles away! Using Honeycrisp, Spartan, or Coutts #28 pear as examples, they would have probably all survived the winter at the Municipal Airport, yet would have certainly been totally killed if they were planted at Fort Edmonton Park, only a few miles away.
The moral of this story is always plant our most tender fruit tree varieties on our highest elevation land, even if it’s only 2 or 3 feet higher. And if you really want a tender variety to have its optimal chance at survival – topwork the variety up high, 8-10 ft. off the ground, to give it the warmest temperatures in a frigid winter. Also trees planted immediately beside a Spruce tree hedge are also protected to a degree. The Spruce trees block much of the wind, as well as absorbing some heat during the day and releasing it at night, at least to some minor degree.
So the best of luck to everyone this winter! With an El Nino winter this year, I doubt we will have any winterkill problems. But this is Alberta, and we all know another test winter will surely arrive sooner or later, so we may as well be as prepared as possible.
These two pictures above demonstrate the way Russians grow tender fruit trees low to the ground and under the snow. The second photo shows another technique where all the branches come out very low, under the winter snow, so that in the event of a test winter, the tree regrows very quickly even if the branches die above the snow line. The vascular system is alive and fully healthy under the snow. But if the branches come out above the snowline as we grow them in Canada, the vascular system is damaged even if the tree survives above the snow, and often the tree declines and dies after a couple of years.
My run with Goji Berry – Part 2 By Thean Pheh
Goji belongs to the Genus, Lycium. There are several species; several are native to North America. The two species planted commercially for their berries are Lycium barbarum and Lycium chinensis, both native to Asia. The former is more popular.
Goji is easily propagated via seeds or cuttings. Seeds can be extracted from fresh berries obtained from local growers or purchased dried goji. I found too much variation in hardiness from plants grown from seeds, even locally grown self-pollinated ones. Since goji roots well with cuttings I see no reason for propagating any from seeds. Both leafless hardwood cuttings taken before bud break in spring and leafy semi-hardwood cuttings taken in early July root well. I treat my cuttings with rooting hormone with 1% IBA. My rooting medium is 1:2 peat moss and perlite by volume. I prefer leafless cuttings as there is no need for modified environment. Leafy cuttings must be placed in a modified environment like misting bed where high humidity can be maintained until the cuttings have rooted. Without the luxury of a misting bed I place my leafy cuttings in a cold frame placed in the shade and mist the inside once a day with a sprayer. Another reason for vegetative propagation is the extremely short juvenile phase. Most of my rooted cutting fruit the following year.
Old literature placed goji as hardy to Zone 4 but it has been known to grow well in Zone 3. It is an adaptable plant, tolerating a wide range of soil conditions, sandy to clayey, acidic to alkaline, even slightly saline soil. It is drought tolerant but will not tolerate wet feet. However, the berries will develop bitterness when the plants are under stress – moisture or soil fertility. Full sun exposure is preferred for good production but it will tolerate some shading. Like all members of the Solanacaea family it loves nitrogen. However excessive nitrogen leads to heavy winterkill.
Goji is best trained as a multiple stem bush. But, it is not an easy plant to train particularly during the young stage. It is a bush but when young it behaves like a vine, resulting in unruly wild growth. Since growth continues till frost, some parts of the plants particularly the tips are most often not harden sufficiently for winter. Hence some tip kill is to be expected. As it may be difficult to differentiate dead from live wood, pruning is best done after the buds break in spring. Dormant buds are not the typical we see in other plants. Like kiwi, dormant buds are within the bark. Another bad characteristic is some small laterals do not terminate with a bud and these died the following year resulting in short pointed protrusions much like those on hawthorn or native plums.
Goji is planted exclusively for its bright dark orange or red berries. The hermaphrodite flowers are typical of all members of the Solanacaea. It is self-fruitful, and even without pollinating insects, the floral arrangement is such that any movement of the branch, for example caused by wind, is sufficient to drop the pollens onto the stigma. There are two flowering periods. In the Edmonton area floral buds initiated last year will grow on emerging shoots and bloom in late May or early June. This blooming period is very short. As the shoots continue to elongate more floral buds are initiated. These will bloom from late June until frost. Berries from the first batch of flowers will ripen in early July. Those from the second batch will ripen in late July or early August until frost. Hence, not all the berries ripen at the same time. From July till frost floral buds, purple flowers, green berries and ripe red berries can be found together on the bush. Harvesting must be done by hand over a long period and it can be tedious and taxing.
Ripe berries are edible as fresh berries. They are soft, juicy and slightly sweet. Some have a slight bitter after-taste while some are bitter. It is not known if this is due to genetics but I know even those with sweet berries can develop mild bitterness when the plants are under moisture stress. The preferred method for storing excess berries is drying. Improper drying process can result in berries turning to an unappetizing black instead of dark red. My preferred storing method is freezing. Ripe berries left on the bush will eventually dry to raisin consistency in winter and can be harvested in March – you can say goji is the first fruit of the year. An interesting thing I found was even bitter berries turn sweet when left to dry on the bush over the winter.
Although the Chinese considered goji leaves to be very nutritious, they grow a selection specifically grown for their bigger, broader and more tender leaves. This selection is called goji choi. Even in metropolitan Edmonton, goji choi dies to the soil level every winter but regrowth is very vigorous, 15 feet is common in my yard. How far north will goji choi grow? I don’t know but I know it was grown successfully in Barrhead. In my yard it flowers readily but I have never seen it set any berry unless I hand pollinate the flowers with pollen collected from goji. Apparently the leaves are very nutritious. Since it is a member of the Solanacaea family I would not eat the leaves in the raw stage for example as salad. We always cook the leaves before eating.
So far I have not encountered any serious disease or insect pest on my goji or goji choi. Birds like robins or Bohemian Waxwing are my most serious pests. Lately the crows and magpies have taken a liking for the berries in late summer. Slugs can be a slight nuisance in very wet years.
In Edmonton dried goji berries are readily available in all Chinese, Korean and Vietnamese herbal and even grocery shops. Health food stores also sell dried goji berries. There are various grades and prices. Apart from appearance I don’t know the difference and I guess you get what you pay. Goji juice is gaining popularity and sold in many outlets. There is even chocolate covered goji berry and bars. Goji choi is only sold in Chinese grocery shops. They are very seasonal and available for a short period only.
Goji is easily propagated via seeds or cuttings. Seeds can be extracted from fresh berries obtained from local growers or purchased dried goji. I found too much variation in hardiness from plants grown from seeds, even locally grown self-pollinated ones. Since goji roots well with cuttings I see no reason for propagating any from seeds. Both leafless hardwood cuttings taken before bud break in spring and leafy semi-hardwood cuttings taken in early July root well. I treat my cuttings with rooting hormone with 1% IBA. My rooting medium is 1:2 peat moss and perlite by volume. I prefer leafless cuttings as there is no need for modified environment. Leafy cuttings must be placed in a modified environment like misting bed where high humidity can be maintained until the cuttings have rooted. Without the luxury of a misting bed I place my leafy cuttings in a cold frame placed in the shade and mist the inside once a day with a sprayer. Another reason for vegetative propagation is the extremely short juvenile phase. Most of my rooted cutting fruit the following year.
Old literature placed goji as hardy to Zone 4 but it has been known to grow well in Zone 3. It is an adaptable plant, tolerating a wide range of soil conditions, sandy to clayey, acidic to alkaline, even slightly saline soil. It is drought tolerant but will not tolerate wet feet. However, the berries will develop bitterness when the plants are under stress – moisture or soil fertility. Full sun exposure is preferred for good production but it will tolerate some shading. Like all members of the Solanacaea family it loves nitrogen. However excessive nitrogen leads to heavy winterkill.
Goji is best trained as a multiple stem bush. But, it is not an easy plant to train particularly during the young stage. It is a bush but when young it behaves like a vine, resulting in unruly wild growth. Since growth continues till frost, some parts of the plants particularly the tips are most often not harden sufficiently for winter. Hence some tip kill is to be expected. As it may be difficult to differentiate dead from live wood, pruning is best done after the buds break in spring. Dormant buds are not the typical we see in other plants. Like kiwi, dormant buds are within the bark. Another bad characteristic is some small laterals do not terminate with a bud and these died the following year resulting in short pointed protrusions much like those on hawthorn or native plums.
Goji is planted exclusively for its bright dark orange or red berries. The hermaphrodite flowers are typical of all members of the Solanacaea. It is self-fruitful, and even without pollinating insects, the floral arrangement is such that any movement of the branch, for example caused by wind, is sufficient to drop the pollens onto the stigma. There are two flowering periods. In the Edmonton area floral buds initiated last year will grow on emerging shoots and bloom in late May or early June. This blooming period is very short. As the shoots continue to elongate more floral buds are initiated. These will bloom from late June until frost. Berries from the first batch of flowers will ripen in early July. Those from the second batch will ripen in late July or early August until frost. Hence, not all the berries ripen at the same time. From July till frost floral buds, purple flowers, green berries and ripe red berries can be found together on the bush. Harvesting must be done by hand over a long period and it can be tedious and taxing.
Ripe berries are edible as fresh berries. They are soft, juicy and slightly sweet. Some have a slight bitter after-taste while some are bitter. It is not known if this is due to genetics but I know even those with sweet berries can develop mild bitterness when the plants are under moisture stress. The preferred method for storing excess berries is drying. Improper drying process can result in berries turning to an unappetizing black instead of dark red. My preferred storing method is freezing. Ripe berries left on the bush will eventually dry to raisin consistency in winter and can be harvested in March – you can say goji is the first fruit of the year. An interesting thing I found was even bitter berries turn sweet when left to dry on the bush over the winter.
Although the Chinese considered goji leaves to be very nutritious, they grow a selection specifically grown for their bigger, broader and more tender leaves. This selection is called goji choi. Even in metropolitan Edmonton, goji choi dies to the soil level every winter but regrowth is very vigorous, 15 feet is common in my yard. How far north will goji choi grow? I don’t know but I know it was grown successfully in Barrhead. In my yard it flowers readily but I have never seen it set any berry unless I hand pollinate the flowers with pollen collected from goji. Apparently the leaves are very nutritious. Since it is a member of the Solanacaea family I would not eat the leaves in the raw stage for example as salad. We always cook the leaves before eating.
So far I have not encountered any serious disease or insect pest on my goji or goji choi. Birds like robins or Bohemian Waxwing are my most serious pests. Lately the crows and magpies have taken a liking for the berries in late summer. Slugs can be a slight nuisance in very wet years.
In Edmonton dried goji berries are readily available in all Chinese, Korean and Vietnamese herbal and even grocery shops. Health food stores also sell dried goji berries. There are various grades and prices. Apart from appearance I don’t know the difference and I guess you get what you pay. Goji juice is gaining popularity and sold in many outlets. There is even chocolate covered goji berry and bars. Goji choi is only sold in Chinese grocery shops. They are very seasonal and available for a short period only.
Goji berry plant in Jo's orchard was purchased in Edmonton Costco for about $12 in summer of 2014
Pictures taken summer of 2015, Jo's orchard is outside of Edmonton city to the NW
Pictures taken summer of 2015, Jo's orchard is outside of Edmonton city to the NW
DBG Fruit Growers’ Bulletin 4-15 by Thean Pheh added October 6, 2015
2015 Fruit Show
Special thanks go to the13 members who brought samples for the show, and came to lend a helping hand to educate the public on Sunday. Special thanks also to Shannon for directing the groups of volunteers and members in setting up the display tables and taking down the display at the end of the day.
In spite of the very dry growing season followed by heavy rain at ripening that resulted in many ruined fruits especially members of the stone fruits there was good representations at the display. Total numbers of fruits on display were 81 Malus (78 known cultivars of apples, applecrabs and crabs and 3 unknown), 3 cherries, 3 chums, 1 Mountain Ash, 1 Elderberry, 1 Goji, 2 Grapes, 1 Korean cherry, 12 pears, 1 Hawthorn and 14 plums.
My run with Goji Berry – Part 1 By Thean Pheh
I ate goji once in awhile since I was big enough to eat solid food. Other than knowing it is good for health we never thought of it as super food. In fact my uncle, a Traditional Chinese Medicine practitioner, warned us over consumption will lead to serious consequences. However with the latest craze for the elixir of life it has become one of the latest super foods. When I typed in goji, and Lycium (it’s Genus nomenclature), Google returned over 13 million and 630 thousand hits respectively. This demonstrates the obsession for this tiny berry. Many gardeners totted this as a new fruit for Alberta. But in reality it had been planted in Edmonton for over a hundred years; perhaps just as long as apples.
When I settled in Edmonton in 1982 it was difficult to buy Asian groceries. I came to know there were two only Chinese grocery shops, one on Jasper Avenue (near WWW Arcade) and the other on Whyte Avenue (just south of the Old Strathcona Farmers’ Market.) Unfortunately both are no longer in business. It was only later that I found there were Vietnamese, Japanese and Korean groceries around. Between the two Chinese groceries I visited the one on Jasper Avenue more often. On one of the trips when I was purchasing dried goji berry I casually asked the elderly owner if goji could be planted in Edmonton. He pointed to the hill slope on the other side of the road and said it was planted with goji. When he saw the doubt in my face he proceeded to relate the history. According to him there were Chinese laborers who opted to settle in Edmonton after their job of helping with the construction of the Canadian Pacific Railway was completed. Goji, an important culinary and medicinal herb, was not readily available, and very expensive in those days. So they planted that slope with seedlings that they germinated with seeds extracted from imported dried fruits. With better air transportation prices of dried goji took a nose dive and more importantly was readily available. The plot was thus abandoned. I treated his narrative as fiction. A couple of years later, the Director of the Alberta Tree Nursery and Horticulture Centre gave me a handful of fresh berries that he called Keedoberry. Although I have never seen a fresh berry, from the seeds and taste I was sure they were goji. He told me he picked them from a test plot in the Research Station in Brooks and asked me to germinate the seeds and plant the seedlings in the field. I was excited and did as instructed but sadly every plant was completely winterkilled. That convinced me the old man was spinning tall tales.
A year or two went by before a man brought several twigs for identification. The Information Officer could not identify them and asked if I knew what they were. After identifying it I asked the man where he got the twigs from. He said he was working on the construction of the Shaw’s Conference Center (SCC) and found it strange that there were so many plants on the slope, and he wanted to know what they were. I immediately recalled the old man’s story and decided to check. By the time I took action the slope was naked and wounded but I found a bush by the cyclist track. I did not know its age but it was very, very old. It was huge, around 8 to 10 feet tall and twice as wide. The canopy was a tangle mess from decades of neglect: so tangled I was positive there must be a couple of wren’s nests in it.
In 2002 I was moved to Brooks and immediately started to search the library for files. Not a single trace of written evidence was left behind. Besides a couple of employees remembering there was such a trial there was not a bush in sight. One evening I walked through the Arboretum and found a single bush. Amazingly even those two employees did not know about it. Besides regular mowing of the grasses, the bush, like other plants in the Arboretum, was totally neglected. It was unhealthy with dead canes throughout; looked like it was on its last leg but it did produce a few disappointingly tiny berries. The birds got most of them but I managed to pick and tasted a couple. They were juicy and sweet. In my last year as a Public employee, my supervisor told me of the huge potential of goji. I disagreed on the grounds that unless there is an embargo there is no way we can compete with China where vast areas were planted, and in many places they were planted as shelterbelts; the berries are merely by-products. Harvesting is very labor intensive but with very cheap labor, dried berries from China are dirt cheap and readily available. Nevertheless I believed (and still do) goji is a potential plant for edible landscaping in Zone 3 across Canada. It may even be a viable small cottage industry for those interested in value-adding. I left Brooks in 2007 but before I left I took some cuttings from that bush but sadly a mini tornado blew everything (propagation trays and other small appliances) away to the next county.
Back in Edmonton each time I saw bushes in people’s yards I dropped in and asked to sample a berry or two. So far every gardener was happy to share fruits and information. They either inherited the plants when they bought the properties or from friends. A handful could trace the origins to the SCC or the McDonald Hotel or somewhere on that slope. I also noted differences in taste, some were sweet, others left a lingering bitter taste; one bush was exceedingly bitter. With that I decided to do some selection. While it was impossible to buy a plant from any nursery a decade ago, goji plants are now sold by almost every nursery in Edmonton.
This and That
* I noted much fewer Apple Maggots in my yard this year. Other members also reported the same. I believe Mother Nature gave us a helping hand for the last couple of years. We had two consecutive cold falls when the snow did not come till end of December. They were not the regular cold but sudden drastic drop in temperature for a night or two now and then. These sudden drops must have taken some toll on the larvae and pupae. Last spring was very wet and cold and this spring was hot and very dry. Both must have hindered and delayed emergence of the adults.
* Hope you still remember the two tiny insects that I brought to our annual fall ‘pilgrimage’ last year. From samples collected this summer Dr. Ken Fry just confirmed one is the Black Currant Weevil, Pseudanthonomus validus, first reported as far back as 1916. So the next time you think your small fruits and berries are destroyed by the Currant Fruit Fly, please think of the Pseudanthonomus. Please refer to DBG Bulletin 5 for more information.
* The second insect was what I thought was the Cherry Sawfly. Dr. Fry is sending samples for positive identification. Hopefully we shall get to know what this pest is.
* Apple curculio and plum curculio have been attacking my saskatoons for many years but had left my apples, pears and plums alone. However over the last couple of years I am seeing more and more damages on these three fruits. At this apple show I saw damages on several pears and apples. Please be on a lookout for these two old pests.
* For me, the much drier than normal spring and summer meant heavier June drop but most of the fruits that remained were bigger. However when the chums and Japanese plums were ripening heavy rain fell and all the chums and plums split and cracked. The Mont Royale was only starting to ripen and did not suffer as much damages; only a few had minor cracks. A couple of our members also reported the same fate.
Special thanks go to the13 members who brought samples for the show, and came to lend a helping hand to educate the public on Sunday. Special thanks also to Shannon for directing the groups of volunteers and members in setting up the display tables and taking down the display at the end of the day.
In spite of the very dry growing season followed by heavy rain at ripening that resulted in many ruined fruits especially members of the stone fruits there was good representations at the display. Total numbers of fruits on display were 81 Malus (78 known cultivars of apples, applecrabs and crabs and 3 unknown), 3 cherries, 3 chums, 1 Mountain Ash, 1 Elderberry, 1 Goji, 2 Grapes, 1 Korean cherry, 12 pears, 1 Hawthorn and 14 plums.
My run with Goji Berry – Part 1 By Thean Pheh
I ate goji once in awhile since I was big enough to eat solid food. Other than knowing it is good for health we never thought of it as super food. In fact my uncle, a Traditional Chinese Medicine practitioner, warned us over consumption will lead to serious consequences. However with the latest craze for the elixir of life it has become one of the latest super foods. When I typed in goji, and Lycium (it’s Genus nomenclature), Google returned over 13 million and 630 thousand hits respectively. This demonstrates the obsession for this tiny berry. Many gardeners totted this as a new fruit for Alberta. But in reality it had been planted in Edmonton for over a hundred years; perhaps just as long as apples.
When I settled in Edmonton in 1982 it was difficult to buy Asian groceries. I came to know there were two only Chinese grocery shops, one on Jasper Avenue (near WWW Arcade) and the other on Whyte Avenue (just south of the Old Strathcona Farmers’ Market.) Unfortunately both are no longer in business. It was only later that I found there were Vietnamese, Japanese and Korean groceries around. Between the two Chinese groceries I visited the one on Jasper Avenue more often. On one of the trips when I was purchasing dried goji berry I casually asked the elderly owner if goji could be planted in Edmonton. He pointed to the hill slope on the other side of the road and said it was planted with goji. When he saw the doubt in my face he proceeded to relate the history. According to him there were Chinese laborers who opted to settle in Edmonton after their job of helping with the construction of the Canadian Pacific Railway was completed. Goji, an important culinary and medicinal herb, was not readily available, and very expensive in those days. So they planted that slope with seedlings that they germinated with seeds extracted from imported dried fruits. With better air transportation prices of dried goji took a nose dive and more importantly was readily available. The plot was thus abandoned. I treated his narrative as fiction. A couple of years later, the Director of the Alberta Tree Nursery and Horticulture Centre gave me a handful of fresh berries that he called Keedoberry. Although I have never seen a fresh berry, from the seeds and taste I was sure they were goji. He told me he picked them from a test plot in the Research Station in Brooks and asked me to germinate the seeds and plant the seedlings in the field. I was excited and did as instructed but sadly every plant was completely winterkilled. That convinced me the old man was spinning tall tales.
A year or two went by before a man brought several twigs for identification. The Information Officer could not identify them and asked if I knew what they were. After identifying it I asked the man where he got the twigs from. He said he was working on the construction of the Shaw’s Conference Center (SCC) and found it strange that there were so many plants on the slope, and he wanted to know what they were. I immediately recalled the old man’s story and decided to check. By the time I took action the slope was naked and wounded but I found a bush by the cyclist track. I did not know its age but it was very, very old. It was huge, around 8 to 10 feet tall and twice as wide. The canopy was a tangle mess from decades of neglect: so tangled I was positive there must be a couple of wren’s nests in it.
In 2002 I was moved to Brooks and immediately started to search the library for files. Not a single trace of written evidence was left behind. Besides a couple of employees remembering there was such a trial there was not a bush in sight. One evening I walked through the Arboretum and found a single bush. Amazingly even those two employees did not know about it. Besides regular mowing of the grasses, the bush, like other plants in the Arboretum, was totally neglected. It was unhealthy with dead canes throughout; looked like it was on its last leg but it did produce a few disappointingly tiny berries. The birds got most of them but I managed to pick and tasted a couple. They were juicy and sweet. In my last year as a Public employee, my supervisor told me of the huge potential of goji. I disagreed on the grounds that unless there is an embargo there is no way we can compete with China where vast areas were planted, and in many places they were planted as shelterbelts; the berries are merely by-products. Harvesting is very labor intensive but with very cheap labor, dried berries from China are dirt cheap and readily available. Nevertheless I believed (and still do) goji is a potential plant for edible landscaping in Zone 3 across Canada. It may even be a viable small cottage industry for those interested in value-adding. I left Brooks in 2007 but before I left I took some cuttings from that bush but sadly a mini tornado blew everything (propagation trays and other small appliances) away to the next county.
Back in Edmonton each time I saw bushes in people’s yards I dropped in and asked to sample a berry or two. So far every gardener was happy to share fruits and information. They either inherited the plants when they bought the properties or from friends. A handful could trace the origins to the SCC or the McDonald Hotel or somewhere on that slope. I also noted differences in taste, some were sweet, others left a lingering bitter taste; one bush was exceedingly bitter. With that I decided to do some selection. While it was impossible to buy a plant from any nursery a decade ago, goji plants are now sold by almost every nursery in Edmonton.
This and That
* I noted much fewer Apple Maggots in my yard this year. Other members also reported the same. I believe Mother Nature gave us a helping hand for the last couple of years. We had two consecutive cold falls when the snow did not come till end of December. They were not the regular cold but sudden drastic drop in temperature for a night or two now and then. These sudden drops must have taken some toll on the larvae and pupae. Last spring was very wet and cold and this spring was hot and very dry. Both must have hindered and delayed emergence of the adults.
* Hope you still remember the two tiny insects that I brought to our annual fall ‘pilgrimage’ last year. From samples collected this summer Dr. Ken Fry just confirmed one is the Black Currant Weevil, Pseudanthonomus validus, first reported as far back as 1916. So the next time you think your small fruits and berries are destroyed by the Currant Fruit Fly, please think of the Pseudanthonomus. Please refer to DBG Bulletin 5 for more information.
* The second insect was what I thought was the Cherry Sawfly. Dr. Fry is sending samples for positive identification. Hopefully we shall get to know what this pest is.
* Apple curculio and plum curculio have been attacking my saskatoons for many years but had left my apples, pears and plums alone. However over the last couple of years I am seeing more and more damages on these three fruits. At this apple show I saw damages on several pears and apples. Please be on a lookout for these two old pests.
* For me, the much drier than normal spring and summer meant heavier June drop but most of the fruits that remained were bigger. However when the chums and Japanese plums were ripening heavy rain fell and all the chums and plums split and cracked. The Mont Royale was only starting to ripen and did not suffer as much damages; only a few had minor cracks. A couple of our members also reported the same fate.
Pruning Workshop Results from Crop Diversification Centre NE Edmonton Aug 20, 2015
A Note from Jeff R. from Crop Diversification Centre
"I hope that you and the association are doing well and have had a great summer so far. The work that you and the group did at our office was fantastic and greatly appreciated. The apple trees are doing very well, a few of them are having a very productive year. Attached are a few pictures of the success!" Go to near bottom of this page to see the before pictures taken on April 4, 2015
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DBG Fruit Growers’ Bulletin 3-15 - by Thean Pheh and Bernie Nikolai added July 11, 2015
New Dwarf Pear Rootstock for zone 2/3 By Bernie Nikolai
One of the problems with pears on the prairies is the lack of dwarfing rootstocks. A pear tree on standard (Siberian Pear) can be a very large tree after a few decades of growth. But there is a new dwarf rootstock, inexpensive and commonly available, and fully hardy in zone 2 and 3 that has been working well in tests in Russia.
The rootstock is Cotoneaster lucidus, the common hedge plant that is growing throughout Edmonton. According to tests in Russia, cotoneaster makes for a dwarf rootstock for pears that only grows to a maximum of about 8 ft. tall after several years. The rootstock can be very long lived, and pear trees in Russia on cotoneaster have lived and produced for over 60 years!
Another advantage of cotoneaster as a pear rootstock is increased hardiness of the grafted on pear cultivar. In a very cold test winter in Siberia with temperatures down to –52C, the very hardy pear ‘Better Safe’ died totally to the snowline when Siberian Pear was used as a rootstock. However the same variety grafted onto cotoneaster had significant winter injury to some main branches, but survived and recovered nicely above the snowline! According to the article I read via Google Translate from a magazine called “Gardens of Siberia”, the author is convinced cotoneaster rootstock causes the pear graft to “harden off for winter” two or three weeks earlier than ordinary pear rootstock. This can be a significant advantage, especially if we get very cold temperatures early in the winter, as we did last November.
According to the author of the article, the pears are full sized, and often even slightly larger than pears grafted on pear rootstock if grafted onto cotoneaster. The taste also seems to be slightly superior as well. Another big advantage is the tree bears fruit starting in year 3 or 4 , vrs years 7-10 when grafted on standard rootstock.
So in a nutshell, the advantages of pear grafted on cotoneaster are as follows:
1/ a dwarf pear tree that only grows to 6-8 ft. tall
2/ Very early production in years 3 or 4 compared to about double that on standard pear rootstock
3/ Slightly larger size and better taste vs. pears grown on standard rootstock
4/ Increased hardiness due to early inducement of “hardening off” for winter by at least 2 weeks over standard pear rootstock
5/ yields are in the range of 25 kg. of pears per tree after a few years annually
There are several different varieties of cotoneaster, and the one commonly available in the Edmonton area is Cotoneaster lucidus. This is a very tough and hardy plant, rated down to zone 2A, that takes drought, urban pollution, and challenging conditions. The variety mentioned in the Russian article was “Bright”, but this appears to be a local name for lucidus from what it appears. The climate conditions in south west Siberia where the tests were done would correspond to about zone 2 here in Canada, with a test winter dropping to slightly below –50C, but very rarely. The “average” winter minimums in the test area were about –37C to –42C annually, very similar to prairie Canada.
However please note THERE IS A “SECRET” THAT MUST BE FOLLOWED when you graft pear onto cotoneaster, or the graft and tree will almost certainly die after a year or two. As a matter of fact tests have been done in Canada, and the result was the pear trees almost always died after a very few years, and cotoneaster was judged as being incompatible with pears for the long term. How then do the Russians get pear trees on cotoneaster to survive for over a half century?
THE KEY IS AT LEAST A COUPLE OF COTONEASTER BRANCHES MUST BE ALLOWED TO GROW ON THE TRUNK OF THE TREE, BELOW THE PEAR GRAFT, BUT ABOVE THE SOIL LINE.
Apparently the cotoneaster root is very good at feeding the pear graft. However the pear graft is poor at sending nutrition back down to the roots. After a couple of years without a few cotoneaster branches feeding the roots, the roots die, and the entire pear tree dies. So a number of cotoneaster shoots MUST be allowed to grow and feed the roots. The exact number is not mentioned, but from the photos I saw it appears to be 2-5 cotoneaster branches. These must be on the main trunk of the tree under the pear graft. Any shoots that pop up from the ground of cotoneaster are routinely cut off.
But will cotoneaster work for us in Alberta as a dwarf and hardy pear rootstock? The FUN of the hobby is experimenting, and that is exactly what I am doing. Last spring I bought a 2 year old cotoneaster in a pot at Home Depot, planted it, and grafted on ‘Northbrite’ pear, a new hardy seedling from Quebec that is supposed to be zone 3 hardy with fruits of commercial quality. The graft took well, and produced a 3 ft. whip last summer. This spring it leafed out fully to the tips, and sent out numerous side branches and looks to be a very healthy 4 ft. pear tree as I write. I did leave 2 cotoneaster branches under the graft union but above the soil level to feed the roots. So far so good!
I continued the tests this spring and grafted various pears onto cotoneaster in 2 gallon pots in my backyard greenhouse. Once they took well, I planted them outside, about 4 ft. apart in my backyard. I now have the following seven pear varieties growing well on cotoneaster: Krasnobokaya, Krazulya, Nick, Successful Falkenberg, Bolshaya, Julienne, and Northbrite. So far so good, and the grafts are about 18” tall the first week in July and doing very well.
As a matter of further testing, Evelyn Mellot, one of our members from Athabasca, has a pear tree she grafted on cotoneaster about 4 years ago. This year it bloomed heavily and hopefully she will get pears this year! Evelyn can’t recall the pear variety she grafted on, more or less as a lark for fun, but if the tree produces it should be easy to identify this fall. It has been fully hardy in zone 2 in the Athabasca region, and is about 6 ft. tall now.
So if you are looking to join the fun and testing, try a few cotoneaster plants and graft pears onto them! There are some very tasty and hardy full sized pears now available to our group, and I don’t want to be the only one with all these wonderful dwarf pear trees in my backyard!
Footnote by Thean
* C. lucidus is native to northern part of Asia. In Alberta it is widely sold and commonly called hedge or shiny cotoneaster (hedge because that what it is used for and shiny, as Bernie rightly pointed out, is a direct translation of its botanical name).
* Before tissue culture in the 90’s, C. lucidus was widely used for propagating saskatoons in Canada.
* Please remember it is very prone to the common diseases of apples and pears such as fireblight and canker, especially the former, and very attractive to oyster scales.
* Like any inter-genera grafts, in this case Pyrus onto Cotoneaster, flow of manufactured food is restricted at the union, eventually leading to death of the roots. Allowing the rootstock to have a couple of branches (laterals) to feed itself circumvent the problem. This practice is well known and the laterals are called Nurse Branches. This same procedure must also be practice if you use saskatoon as rootstock for pears.
Pollinating Insects By Thean Pheh
At last year’s Fruit Show, Konrad made a very interesting comment: he said his honeybees do not like to visit chum (cherryplum) flowers. Since I have not had honeybees visiting my garden for more than a decade I could not comment on his observation. (Hopefully now that Edmontonians are allowed to keep honeybees within the city I’ll be getting some visitors in the near future.) I know some of you have apiary and if you have seen the same phenomenon please enlighten us.
Without honeybees I depend on other insects, especially native bees, to pollinate my fruit trees. This spring I followed up on Konrad’s observation and found it amusing. Chums’ flowers are unattractive to native bees too. Native bees were all over the various fruits and berries. However, I did not see any on the chums or pears. Smell is a more powerful attractant than sight for insects to home in on their food. I am a little puzzled; since chum flowers smell very similar to those of the plum, why are these bees visiting the plums and not the chums? Or, is my nose all messed up and cannot detect minor differences? Since my single pear tree set fairly well and there are a few fruits on the chums, either the bees were visiting these plants behind my back or the nocturnal insects are doing a good job.
Honeybees’ social behavior and ease of management have resulted in their domestication and economic importance. (They were originally domesticated for honey production, not for pollination.) But, they have been given far too much credit in fruit production. While there is no doubt that honeybees are excellent pollinating agents, they did not make it to the Americas until the arrival of Europeans. That being the case how did First Nation people across the North and the South American Continents harvest bountiful fruits, nuts and berries for thousands of years before Europeans stepped ashore? The answer is native bees and various other insects and animals. While honeybees are good in that they are dual purpose, providing pollination and honey, they are very demanding and highly ‘unionized’: a bee assigned to collect nectar and pollen will not perform any other task, neither will a guard bee do anything besides guarding the hive. Honeybees will not leave the hives if the temperature is too low (below 13oC) or the wind is too strong. A few of our fruits flower very early in spring at a time when the temperature is still too cool for the honeybees to venture out. Native bees are less demanding and will work when honeybees are ‘walking the picket line’. (Actually, they don’t even walk, they just hunker down in tight groups in the comfort of the hive.) However, while honeybees will forage miles from home native bees are very homely; rarely foraging more than a few hundred yards from their birthplace. Insects are generally docile but guard honeybees will attack if their hives are threatened or invaded. Native bees are more docile, unless squeezed between your fingers or body and clothing they do not sting even when your face is inches from their nests. Even then their stings are much, much less painful.
Laziness caused me to take things for granted and I thought the native bees I had depended on were bumblebees and Orchard Mason Bees. With that in mind I made and put up a housing block with ¼” holes. Since almost every hole was used I believed I was correct. However, with closer observation this spring, (Thank you, Konrad, for making me think) I am surprise and ashamed I was wrong, dead wrong all these years. There were many types of insects pollinating my fruit trees and bushes. Among the insects I saw this spring were several native bees (bumblebees, mason bees, Andrenid bees, and many others I cannot identify), wasps, thrips, sawflies, hover flies, house flies and ants. I believe, wasps, hover flies, house flies and ants are poor carriers of pollens because they have few hairs and these are very course. I particularly dislike ants; their limited usefulness is confined to self-fruitful crops like currants and gooseberries. The other downside is they are also good ‘dairy farmers’, moving and distributing aphids to new shoots. Another troubling bad behavior of ants is they are fond of cutting off the pistils of some fruits particularly Josta currants and apples. Have any of you noted this bad habit? The saskatoon sawfly is another I dislike. Although they are good pollinating agent for saskatoons their larvae destroy too many berries. Nocturnal insects also play important roles in pollination. What a shame it is that I do not know those responsible for the various fruits in Alberta but I’m sure moths and midges are among them. Perhaps getting to know these beneficial nocturnal is a good project for me and you in the coming years. If you already know these please spare me the agony.
Since these insects are very important in fruit growing we must provide incentives for them, especially native bees, to call our garden home. Like all animals, humans included, their basic needs are housing, food and opportunities to ‘raise their young’. In housing, native bees are divided into two groups, ground dwelling and cavity dwelling. Ground dwelling bees, except bumblebees, excavate their own nesting burrows. Their preferred real estate is bare and exposed soil. Bumblebees use existing animal burrows or deserted bird houses (man-made or tree cavities). Cavity dwelling bees, except Carpenter bees, must have existing tunnels to raise their young. Under natural conditions these tunnels are those left behind by the various wood boring insects or any tubular gaps as found in shingles on rooftops, especially wooden shingles. Carpenter bees remove the soft pith of broken branches of plants with big piths like elderberry to create their own housing. All cavity dwelling bees use mud or mud mixed with vegetative materials to separate nesting chambers and seal holes while Leafcutter bees use leaves or petals exclusively.
Ground dwelling bees are the engineers, laborers and mothers all rolled into one; they dig their own nests and perform all the jobs required. As stated above, the exception is bumblebees. Since they prefer undisturbed friable soft soil and I practice zero tillage and do not do any fall cleanup, my entire yard is an ideal prime housing estate for them. However, since most ground dwelling bees prefer bare soil I also leave patches clean. To discourage neighbors’ cats from using these bare spots as toilets I place a few dried twigs on the bare surfaces. If your garden is spic and span, as recommended by ‘the experts’, where every bed is cultivated in spring and clean up and/or dug in fall, just set aside a small area and completely neglect it for these beneficial insects. If you hate to leave the area unplanted, plant tall perennials far apart such that there is ample bare area for the bees to dig.
While Carpenter bees will cut their own tunnels other cavity dwelling bees require readily made holes of specific sizes for housing. Since I had assumed Orchard Mason bees were solely responsible, all my work so far was geared to this insect. All native bees, the exception is bumblebees, are solitary throughout their short life span. Manson bees live solitary life but are gregarious when it comes to housing. They like to nest close to each other, preferring ‘condominiums’ to detached bungalows. Readily made condominiums are available from many nursery outlets. Being cheap I made my own. Unfortunately all literatures on Orchard Mason Bees are on the western subspecies. I do not know if our eastern subspecies’ requirements are the same. Neither do I know how many types of mason bees beside Orchard Mason Bees there are in Alberta. Nonetheless any untreated 2x4, 2x6, 4x4 or log, the older and weathered the better (most literature advises against using cider wood), with a series of ¼” (5.5mm) and 5/16” (8mm) holes is suitable. The bees like holes 4 inches or deeper but have no problem accepting any shallower holes. I cut 2x4 eco stub into 2 feet length and drill 2 rows of hole on the 2” side. The holes are about an inch apart. The holes are drilled at a slight angle and the block so placed that all the holes slope downwards. This is to prevent water from draining into the holes. I hang drilled blocks about 4 feet above the ground. They must be fully exposed and not blocked by other structures or plants. South and east orientations are better as they warm up earlier in the day. That’s it; now that you have built and put up the ‘For sale’ sign, go and do your other chores or enjoy your garden.
Old holes must be cleaned and the bees will start this housekeeping job around middle of May or earlier, depending on the weather. They start laying eggs in a series of chambers, laid end to end, in June. Once the entire length of the hole is used up they will plug it up. Check your condominiums in July. You are a good real estate agent if you see the holes are plugged up but your job is not completed yet. The condominiums must be removed and placed in an unheated place such as the garage or garden shed in late summer unless you are interested in feeding the woodpeckers. Condominiums thus protected can be replaced in early spring, say around early to mid-April. Once replaced, or new ones put up, do not move it around because mason bees home in on recognized landmarks. Since the bees use mud to separate each chamber and to seal the entrances availability of wet soil is important. Keep a spot near the nesting block wet or place a dish with wet mud or soil nearby. Some, for example Leafcutter bees, line and seal their nests with leaves. They particularly like roses’ leaves. Hence if you see fairly big circular or semi-circular holes of around 1/2” on your ornamentals do not be alarmed. It’s a small price to pay for the services delivered.
Food is important to keep the adult bees alive and active, and food stockpile for their larvae. They will hang around as long as they have access to flowers to collect nectar and pollen. The female bees only lived for a short few months in summer and if they cannot find sufficient food they will pull up stakes and moved elsewhere to start new families before they die. Since most fruits only bloom for a very short period in spring, be sure to plant a range of fruits, other flowering plants or ornamentals such that there is a continuous supply of flowers from late April or early May till at least end of July. In terms of hardy fruits, Haskap is the first to flower and the last is the Black Elderberry (that is assuming they are on new canes). Goji, fall-bearing raspberries and day-neutral strawberries are excellent fruits in that they bloom more or less throughout the growing season with a short break between two peak periods. Part of June is a ‘dry’ period where few fruits are in bloom. This is when ornamentals come in handy. However if you are into edible gardening exclusively, planting vegetables and herbs that bloom around that time will alleviate the problem.
Native bees have their own sets of parasites and diseases. To reduce parasites, it is recommended we give the bees a helping hand by replacing or disinfecting ‘condominiums’ every second year. But, the greatest threat to their survival is pesticides. Use of insecticides must be carefully monitored and weighed. If required, spray after the trees have finished flowering. Soil cultivation in fall is detrimental to ground dwelling bees since cultivating in fall destroys next year’s generation of ground dwelling bees. Woodpeckers are by far the most serious predators of cavity dwelling bees.
Footnote
* A range of hole, from 2/32” to 5/16” (2 mm to 8 mm) is recommended by many in Europe and Australia. After seeing the wide range of native bees in my yard, my next year’s project is to hang a housing block with holes of different diameters and see which sizes are best for my area. Anyone game in joining me on this adventure?
* Another important species of cavity dweller is the Leafcutter bees. I have not seen them around for some time. Neither have they used any existing holes in my housing block. However, since my roses still have their leaves neatly cut they must still be around.
* 2x4 eco studs are much cheaper but they can be knotty. All the 2x4 studs I purchased are either spruce or pine. So far the native bees are avoiding holes that are drilled through knots.
This and That
* The apple maggot season is in full swing. Hope you have heeded Shannon’s advice and had your apples all wrapped already.
* It had been a very dry spring this year. I have seen apple trees heavily laden with flowers only to see 100% of the flowers shriveled up before blooming under the hot sun and dry soil.
* Edmontonians had an earlier ‘spring’ but most also faced a very light frost, not enough to cause much damages to most fruits but sufficiently cold enough to knock off some early flowering plums and other stone fruits. New growth of my Arctic Kiwi was completely frozen – hence zero harvest this year.
* Many of you are ‘old sea dogs’ (to borrow the expression from sailors) and have lots of good tips. Please take the initiative, like Bernie just did, and enlighten all members. Thank you, Bernie.
One of the problems with pears on the prairies is the lack of dwarfing rootstocks. A pear tree on standard (Siberian Pear) can be a very large tree after a few decades of growth. But there is a new dwarf rootstock, inexpensive and commonly available, and fully hardy in zone 2 and 3 that has been working well in tests in Russia.
The rootstock is Cotoneaster lucidus, the common hedge plant that is growing throughout Edmonton. According to tests in Russia, cotoneaster makes for a dwarf rootstock for pears that only grows to a maximum of about 8 ft. tall after several years. The rootstock can be very long lived, and pear trees in Russia on cotoneaster have lived and produced for over 60 years!
Another advantage of cotoneaster as a pear rootstock is increased hardiness of the grafted on pear cultivar. In a very cold test winter in Siberia with temperatures down to –52C, the very hardy pear ‘Better Safe’ died totally to the snowline when Siberian Pear was used as a rootstock. However the same variety grafted onto cotoneaster had significant winter injury to some main branches, but survived and recovered nicely above the snowline! According to the article I read via Google Translate from a magazine called “Gardens of Siberia”, the author is convinced cotoneaster rootstock causes the pear graft to “harden off for winter” two or three weeks earlier than ordinary pear rootstock. This can be a significant advantage, especially if we get very cold temperatures early in the winter, as we did last November.
According to the author of the article, the pears are full sized, and often even slightly larger than pears grafted on pear rootstock if grafted onto cotoneaster. The taste also seems to be slightly superior as well. Another big advantage is the tree bears fruit starting in year 3 or 4 , vrs years 7-10 when grafted on standard rootstock.
So in a nutshell, the advantages of pear grafted on cotoneaster are as follows:
1/ a dwarf pear tree that only grows to 6-8 ft. tall
2/ Very early production in years 3 or 4 compared to about double that on standard pear rootstock
3/ Slightly larger size and better taste vs. pears grown on standard rootstock
4/ Increased hardiness due to early inducement of “hardening off” for winter by at least 2 weeks over standard pear rootstock
5/ yields are in the range of 25 kg. of pears per tree after a few years annually
There are several different varieties of cotoneaster, and the one commonly available in the Edmonton area is Cotoneaster lucidus. This is a very tough and hardy plant, rated down to zone 2A, that takes drought, urban pollution, and challenging conditions. The variety mentioned in the Russian article was “Bright”, but this appears to be a local name for lucidus from what it appears. The climate conditions in south west Siberia where the tests were done would correspond to about zone 2 here in Canada, with a test winter dropping to slightly below –50C, but very rarely. The “average” winter minimums in the test area were about –37C to –42C annually, very similar to prairie Canada.
However please note THERE IS A “SECRET” THAT MUST BE FOLLOWED when you graft pear onto cotoneaster, or the graft and tree will almost certainly die after a year or two. As a matter of fact tests have been done in Canada, and the result was the pear trees almost always died after a very few years, and cotoneaster was judged as being incompatible with pears for the long term. How then do the Russians get pear trees on cotoneaster to survive for over a half century?
THE KEY IS AT LEAST A COUPLE OF COTONEASTER BRANCHES MUST BE ALLOWED TO GROW ON THE TRUNK OF THE TREE, BELOW THE PEAR GRAFT, BUT ABOVE THE SOIL LINE.
Apparently the cotoneaster root is very good at feeding the pear graft. However the pear graft is poor at sending nutrition back down to the roots. After a couple of years without a few cotoneaster branches feeding the roots, the roots die, and the entire pear tree dies. So a number of cotoneaster shoots MUST be allowed to grow and feed the roots. The exact number is not mentioned, but from the photos I saw it appears to be 2-5 cotoneaster branches. These must be on the main trunk of the tree under the pear graft. Any shoots that pop up from the ground of cotoneaster are routinely cut off.
But will cotoneaster work for us in Alberta as a dwarf and hardy pear rootstock? The FUN of the hobby is experimenting, and that is exactly what I am doing. Last spring I bought a 2 year old cotoneaster in a pot at Home Depot, planted it, and grafted on ‘Northbrite’ pear, a new hardy seedling from Quebec that is supposed to be zone 3 hardy with fruits of commercial quality. The graft took well, and produced a 3 ft. whip last summer. This spring it leafed out fully to the tips, and sent out numerous side branches and looks to be a very healthy 4 ft. pear tree as I write. I did leave 2 cotoneaster branches under the graft union but above the soil level to feed the roots. So far so good!
I continued the tests this spring and grafted various pears onto cotoneaster in 2 gallon pots in my backyard greenhouse. Once they took well, I planted them outside, about 4 ft. apart in my backyard. I now have the following seven pear varieties growing well on cotoneaster: Krasnobokaya, Krazulya, Nick, Successful Falkenberg, Bolshaya, Julienne, and Northbrite. So far so good, and the grafts are about 18” tall the first week in July and doing very well.
As a matter of further testing, Evelyn Mellot, one of our members from Athabasca, has a pear tree she grafted on cotoneaster about 4 years ago. This year it bloomed heavily and hopefully she will get pears this year! Evelyn can’t recall the pear variety she grafted on, more or less as a lark for fun, but if the tree produces it should be easy to identify this fall. It has been fully hardy in zone 2 in the Athabasca region, and is about 6 ft. tall now.
So if you are looking to join the fun and testing, try a few cotoneaster plants and graft pears onto them! There are some very tasty and hardy full sized pears now available to our group, and I don’t want to be the only one with all these wonderful dwarf pear trees in my backyard!
Footnote by Thean
* C. lucidus is native to northern part of Asia. In Alberta it is widely sold and commonly called hedge or shiny cotoneaster (hedge because that what it is used for and shiny, as Bernie rightly pointed out, is a direct translation of its botanical name).
* Before tissue culture in the 90’s, C. lucidus was widely used for propagating saskatoons in Canada.
* Please remember it is very prone to the common diseases of apples and pears such as fireblight and canker, especially the former, and very attractive to oyster scales.
* Like any inter-genera grafts, in this case Pyrus onto Cotoneaster, flow of manufactured food is restricted at the union, eventually leading to death of the roots. Allowing the rootstock to have a couple of branches (laterals) to feed itself circumvent the problem. This practice is well known and the laterals are called Nurse Branches. This same procedure must also be practice if you use saskatoon as rootstock for pears.
Pollinating Insects By Thean Pheh
At last year’s Fruit Show, Konrad made a very interesting comment: he said his honeybees do not like to visit chum (cherryplum) flowers. Since I have not had honeybees visiting my garden for more than a decade I could not comment on his observation. (Hopefully now that Edmontonians are allowed to keep honeybees within the city I’ll be getting some visitors in the near future.) I know some of you have apiary and if you have seen the same phenomenon please enlighten us.
Without honeybees I depend on other insects, especially native bees, to pollinate my fruit trees. This spring I followed up on Konrad’s observation and found it amusing. Chums’ flowers are unattractive to native bees too. Native bees were all over the various fruits and berries. However, I did not see any on the chums or pears. Smell is a more powerful attractant than sight for insects to home in on their food. I am a little puzzled; since chum flowers smell very similar to those of the plum, why are these bees visiting the plums and not the chums? Or, is my nose all messed up and cannot detect minor differences? Since my single pear tree set fairly well and there are a few fruits on the chums, either the bees were visiting these plants behind my back or the nocturnal insects are doing a good job.
Honeybees’ social behavior and ease of management have resulted in their domestication and economic importance. (They were originally domesticated for honey production, not for pollination.) But, they have been given far too much credit in fruit production. While there is no doubt that honeybees are excellent pollinating agents, they did not make it to the Americas until the arrival of Europeans. That being the case how did First Nation people across the North and the South American Continents harvest bountiful fruits, nuts and berries for thousands of years before Europeans stepped ashore? The answer is native bees and various other insects and animals. While honeybees are good in that they are dual purpose, providing pollination and honey, they are very demanding and highly ‘unionized’: a bee assigned to collect nectar and pollen will not perform any other task, neither will a guard bee do anything besides guarding the hive. Honeybees will not leave the hives if the temperature is too low (below 13oC) or the wind is too strong. A few of our fruits flower very early in spring at a time when the temperature is still too cool for the honeybees to venture out. Native bees are less demanding and will work when honeybees are ‘walking the picket line’. (Actually, they don’t even walk, they just hunker down in tight groups in the comfort of the hive.) However, while honeybees will forage miles from home native bees are very homely; rarely foraging more than a few hundred yards from their birthplace. Insects are generally docile but guard honeybees will attack if their hives are threatened or invaded. Native bees are more docile, unless squeezed between your fingers or body and clothing they do not sting even when your face is inches from their nests. Even then their stings are much, much less painful.
Laziness caused me to take things for granted and I thought the native bees I had depended on were bumblebees and Orchard Mason Bees. With that in mind I made and put up a housing block with ¼” holes. Since almost every hole was used I believed I was correct. However, with closer observation this spring, (Thank you, Konrad, for making me think) I am surprise and ashamed I was wrong, dead wrong all these years. There were many types of insects pollinating my fruit trees and bushes. Among the insects I saw this spring were several native bees (bumblebees, mason bees, Andrenid bees, and many others I cannot identify), wasps, thrips, sawflies, hover flies, house flies and ants. I believe, wasps, hover flies, house flies and ants are poor carriers of pollens because they have few hairs and these are very course. I particularly dislike ants; their limited usefulness is confined to self-fruitful crops like currants and gooseberries. The other downside is they are also good ‘dairy farmers’, moving and distributing aphids to new shoots. Another troubling bad behavior of ants is they are fond of cutting off the pistils of some fruits particularly Josta currants and apples. Have any of you noted this bad habit? The saskatoon sawfly is another I dislike. Although they are good pollinating agent for saskatoons their larvae destroy too many berries. Nocturnal insects also play important roles in pollination. What a shame it is that I do not know those responsible for the various fruits in Alberta but I’m sure moths and midges are among them. Perhaps getting to know these beneficial nocturnal is a good project for me and you in the coming years. If you already know these please spare me the agony.
Since these insects are very important in fruit growing we must provide incentives for them, especially native bees, to call our garden home. Like all animals, humans included, their basic needs are housing, food and opportunities to ‘raise their young’. In housing, native bees are divided into two groups, ground dwelling and cavity dwelling. Ground dwelling bees, except bumblebees, excavate their own nesting burrows. Their preferred real estate is bare and exposed soil. Bumblebees use existing animal burrows or deserted bird houses (man-made or tree cavities). Cavity dwelling bees, except Carpenter bees, must have existing tunnels to raise their young. Under natural conditions these tunnels are those left behind by the various wood boring insects or any tubular gaps as found in shingles on rooftops, especially wooden shingles. Carpenter bees remove the soft pith of broken branches of plants with big piths like elderberry to create their own housing. All cavity dwelling bees use mud or mud mixed with vegetative materials to separate nesting chambers and seal holes while Leafcutter bees use leaves or petals exclusively.
Ground dwelling bees are the engineers, laborers and mothers all rolled into one; they dig their own nests and perform all the jobs required. As stated above, the exception is bumblebees. Since they prefer undisturbed friable soft soil and I practice zero tillage and do not do any fall cleanup, my entire yard is an ideal prime housing estate for them. However, since most ground dwelling bees prefer bare soil I also leave patches clean. To discourage neighbors’ cats from using these bare spots as toilets I place a few dried twigs on the bare surfaces. If your garden is spic and span, as recommended by ‘the experts’, where every bed is cultivated in spring and clean up and/or dug in fall, just set aside a small area and completely neglect it for these beneficial insects. If you hate to leave the area unplanted, plant tall perennials far apart such that there is ample bare area for the bees to dig.
While Carpenter bees will cut their own tunnels other cavity dwelling bees require readily made holes of specific sizes for housing. Since I had assumed Orchard Mason bees were solely responsible, all my work so far was geared to this insect. All native bees, the exception is bumblebees, are solitary throughout their short life span. Manson bees live solitary life but are gregarious when it comes to housing. They like to nest close to each other, preferring ‘condominiums’ to detached bungalows. Readily made condominiums are available from many nursery outlets. Being cheap I made my own. Unfortunately all literatures on Orchard Mason Bees are on the western subspecies. I do not know if our eastern subspecies’ requirements are the same. Neither do I know how many types of mason bees beside Orchard Mason Bees there are in Alberta. Nonetheless any untreated 2x4, 2x6, 4x4 or log, the older and weathered the better (most literature advises against using cider wood), with a series of ¼” (5.5mm) and 5/16” (8mm) holes is suitable. The bees like holes 4 inches or deeper but have no problem accepting any shallower holes. I cut 2x4 eco stub into 2 feet length and drill 2 rows of hole on the 2” side. The holes are about an inch apart. The holes are drilled at a slight angle and the block so placed that all the holes slope downwards. This is to prevent water from draining into the holes. I hang drilled blocks about 4 feet above the ground. They must be fully exposed and not blocked by other structures or plants. South and east orientations are better as they warm up earlier in the day. That’s it; now that you have built and put up the ‘For sale’ sign, go and do your other chores or enjoy your garden.
Old holes must be cleaned and the bees will start this housekeeping job around middle of May or earlier, depending on the weather. They start laying eggs in a series of chambers, laid end to end, in June. Once the entire length of the hole is used up they will plug it up. Check your condominiums in July. You are a good real estate agent if you see the holes are plugged up but your job is not completed yet. The condominiums must be removed and placed in an unheated place such as the garage or garden shed in late summer unless you are interested in feeding the woodpeckers. Condominiums thus protected can be replaced in early spring, say around early to mid-April. Once replaced, or new ones put up, do not move it around because mason bees home in on recognized landmarks. Since the bees use mud to separate each chamber and to seal the entrances availability of wet soil is important. Keep a spot near the nesting block wet or place a dish with wet mud or soil nearby. Some, for example Leafcutter bees, line and seal their nests with leaves. They particularly like roses’ leaves. Hence if you see fairly big circular or semi-circular holes of around 1/2” on your ornamentals do not be alarmed. It’s a small price to pay for the services delivered.
Food is important to keep the adult bees alive and active, and food stockpile for their larvae. They will hang around as long as they have access to flowers to collect nectar and pollen. The female bees only lived for a short few months in summer and if they cannot find sufficient food they will pull up stakes and moved elsewhere to start new families before they die. Since most fruits only bloom for a very short period in spring, be sure to plant a range of fruits, other flowering plants or ornamentals such that there is a continuous supply of flowers from late April or early May till at least end of July. In terms of hardy fruits, Haskap is the first to flower and the last is the Black Elderberry (that is assuming they are on new canes). Goji, fall-bearing raspberries and day-neutral strawberries are excellent fruits in that they bloom more or less throughout the growing season with a short break between two peak periods. Part of June is a ‘dry’ period where few fruits are in bloom. This is when ornamentals come in handy. However if you are into edible gardening exclusively, planting vegetables and herbs that bloom around that time will alleviate the problem.
Native bees have their own sets of parasites and diseases. To reduce parasites, it is recommended we give the bees a helping hand by replacing or disinfecting ‘condominiums’ every second year. But, the greatest threat to their survival is pesticides. Use of insecticides must be carefully monitored and weighed. If required, spray after the trees have finished flowering. Soil cultivation in fall is detrimental to ground dwelling bees since cultivating in fall destroys next year’s generation of ground dwelling bees. Woodpeckers are by far the most serious predators of cavity dwelling bees.
Footnote
* A range of hole, from 2/32” to 5/16” (2 mm to 8 mm) is recommended by many in Europe and Australia. After seeing the wide range of native bees in my yard, my next year’s project is to hang a housing block with holes of different diameters and see which sizes are best for my area. Anyone game in joining me on this adventure?
* Another important species of cavity dweller is the Leafcutter bees. I have not seen them around for some time. Neither have they used any existing holes in my housing block. However, since my roses still have their leaves neatly cut they must still be around.
* 2x4 eco studs are much cheaper but they can be knotty. All the 2x4 studs I purchased are either spruce or pine. So far the native bees are avoiding holes that are drilled through knots.
This and That
* The apple maggot season is in full swing. Hope you have heeded Shannon’s advice and had your apples all wrapped already.
* It had been a very dry spring this year. I have seen apple trees heavily laden with flowers only to see 100% of the flowers shriveled up before blooming under the hot sun and dry soil.
* Edmontonians had an earlier ‘spring’ but most also faced a very light frost, not enough to cause much damages to most fruits but sufficiently cold enough to knock off some early flowering plums and other stone fruits. New growth of my Arctic Kiwi was completely frozen – hence zero harvest this year.
* Many of you are ‘old sea dogs’ (to borrow the expression from sailors) and have lots of good tips. Please take the initiative, like Bernie just did, and enlighten all members. Thank you, Bernie.
DBG Fruit Growers’ Bulletin 2-15 by Thean Pheh added May 1, 2015
Apple Thinning.
In the last issue we talked about the thinning procedure I followed. As we have seen, fruit thinning at the correct time has a direct influence on the fruiting habit, size and qualities of the apples. An average size apple has about 50 million cells. The three factors that influence the maximum size of an apple are number of cells, cell size and intercellular space. Genetic makeup of the clone places maximum limits to these three factors. Those are the ‘Holy Grail’ and there is nothing we can do aside from picking or selecting the correct clone. However, expressions are dependent on genes and environment; scientists call them genotype and phenotype. In our parlance we say genetic expression and physical expressions. The apple’s shape is fixed by genes but the size, color and even texture and taste is the result of interactions between the genes and the environment.
Although genotype places maximum limits (cell number, cell size and intercellular space), normal growing conditions rarely allow the trees to achieve these limits. Please remember we plant trees but can never grow them: trees are one of the very few higher organized organisms that produce their own food and grow by themselves. All our actions are nothing but a helping hand: they are the performers while we are the stage hands providing them the necessary supporting roles. We have no control of the genes but as ‘stage hands’ we can influence the environment to a certain extent. In other words although we cannot touch the ‘Holy Grail’ we can play a role in the physical expressions. Making up for the environmental shortfalls is what is well within our means to help the trees perform their best. Cultural practices well within our means are clone selection, thinning, watering, pruning, fertilizing, pest and disease control.
Since genetic determines the maximum cell number, cell size and intercellular space without a doubt the first step is to select and plant suitably hardy variety that will not sustain any winter injury. As we have learned in the last issue, the amount of stored food a spur can withdraw from its surrounding sapwood and what its spur leaves can generate in early spring is critical; it determines the number of cells in the fruit. This rapid cell division (multiplication in layman’s terms), is completed by June-drop. That means fruit thinning after June-drop would not increase the number of cells in an apple. Hence instead of dividing and dishing the ‘pot onto many plates’ early flower thinning and fruit thinning divert whatever food that’s available to the selected apple, giving it the opportunity to produce the most number of cells within the maximum limit set by the clone.
Generally there is sufficient soil moisture in spring. Air temperature is the limiting factor. The optimum temperature for maximum cell division is around 17oC but ours is like a yoyo. Technically the king fruit has the best potential to be the biggest. But, do not be tempted to retain the king fruits. The bees may have done their job but since the king flower is the first to blossom, pollen growth may be too slow for effective pollination. Even when pollination is successful the low temperatures slow down cell division.
Assuming that we have pruned properly, once thinning is completed our supporting roles comes into full swing. Our actions can greatly influence cell size and intercellular spaces. Make sure there is sufficient soil moisture throughout the summer. Nutrients availability is influenced by soil reaction, salinity and nutrients balances. A pH of 6 to 7 is ideal and the EC reading is best when it is lower than 2dS m-1. Too much of one element may limit the availability of another. A good example is potassium. I know a member of our group who applied liberal amount of Muriate of Potash in late summer to harden his trees. It worked because the extra potash reduces the nitrogen uptake. However, after a few years he found all his trees were suffering from magnesium deficiency because the soil was too heavily loaded with potash.
One factor often overlooked by many is the rootstock. Among other things rootstock can greatly influence the apple size of some clones significantly. A good example I know is Sim Red. At CDCN apples are grafted onto open pollinated Columbia seedlings. Apples on one tree were consistently over 3” across while several trees besides it produced apples that were only slightly bigger than Heyer 12. I am sure some of you have observed the same phenomenon and I love to hear from you. Perhaps rootstock should be the topic of our next issue. If any reader is willing to take on this task, please tell me.
Forest Tent Caterpillars can completely defoliate the entire tree in a short period. This has a direct impact on the fruit size. Trunk Fireblight and canker take some time before they kill the entire branch. However in the meantime their presence causes unthrifty growth and results in smaller apples on the infected branch.
In a nutshell then, to get the biggest apple a particular clone is capable of, we must provide proper pruning, flower and fruit thinning, ensure proper soil pH and EC, optimum soil moisture and control pests and diseases.
This and That
An apple weighing in at 1.849 kg (4 lb 1 oz) on October 24 2005 is still the world’s record largest apple. It was grown by Chisato Iwasaki on his apple farm in Hirosaki City, Japan(1). The variety is Hokuto, a hybrid of two popular Japanese commercial apples, Fuji and Matsu. The record is almost 10 years old. Is anyone game at trying to break it? I do not know if Hokuto will grow here but if I were to attempt at an Alberta record, I would plant Elsie Wagner or Roppic. These are the largest I have seen at our annual fruit show since 1989.
Many of us peel apples before baking. Have you ever thought how long a continuous peel can you make? In 1976, Kathy Wafler Madison, at the tender age of 16, created the world's longest single continuous apple peel. It measured 172 feet, 4 inches long (2). That’s impressive when I could not go beyond three feet.
Research in England found that it takes 30 leaves to produce sufficient energy to grow one full size apple and still have sufficient food reserves to initiate next year’s flowers. Please bear in mind we do not have the growing climate England has and as such I think 30 leaves is a little low for us. The Japanese like big apples and most producers allow 50 leaves for the Japanese trade.
Thinking of making extra money? You might be able to if you are willing to go the extra mile. This year I saw 9 Fuji apples in a box with a price tag of $14.99. These were specifically meant as gifts for the Chinese New year on the 19th of February 2015. Each apple has the Chinese character for prosperity or good luck ‘written by the sun’. The price dropped to $9.88 on the 20th of February.
(1) http://guinnessrecordsworld.blogspot.ca/2011/05/heaviest-apple.html
(2) https://news.google.com/newspapers?nid=2209&dat=19771102&id=hn9jAAAAIBAJ&sjid=3HkNAAAAIBA J&pg=2321,213157&hl=en
In the last issue we talked about the thinning procedure I followed. As we have seen, fruit thinning at the correct time has a direct influence on the fruiting habit, size and qualities of the apples. An average size apple has about 50 million cells. The three factors that influence the maximum size of an apple are number of cells, cell size and intercellular space. Genetic makeup of the clone places maximum limits to these three factors. Those are the ‘Holy Grail’ and there is nothing we can do aside from picking or selecting the correct clone. However, expressions are dependent on genes and environment; scientists call them genotype and phenotype. In our parlance we say genetic expression and physical expressions. The apple’s shape is fixed by genes but the size, color and even texture and taste is the result of interactions between the genes and the environment.
Although genotype places maximum limits (cell number, cell size and intercellular space), normal growing conditions rarely allow the trees to achieve these limits. Please remember we plant trees but can never grow them: trees are one of the very few higher organized organisms that produce their own food and grow by themselves. All our actions are nothing but a helping hand: they are the performers while we are the stage hands providing them the necessary supporting roles. We have no control of the genes but as ‘stage hands’ we can influence the environment to a certain extent. In other words although we cannot touch the ‘Holy Grail’ we can play a role in the physical expressions. Making up for the environmental shortfalls is what is well within our means to help the trees perform their best. Cultural practices well within our means are clone selection, thinning, watering, pruning, fertilizing, pest and disease control.
Since genetic determines the maximum cell number, cell size and intercellular space without a doubt the first step is to select and plant suitably hardy variety that will not sustain any winter injury. As we have learned in the last issue, the amount of stored food a spur can withdraw from its surrounding sapwood and what its spur leaves can generate in early spring is critical; it determines the number of cells in the fruit. This rapid cell division (multiplication in layman’s terms), is completed by June-drop. That means fruit thinning after June-drop would not increase the number of cells in an apple. Hence instead of dividing and dishing the ‘pot onto many plates’ early flower thinning and fruit thinning divert whatever food that’s available to the selected apple, giving it the opportunity to produce the most number of cells within the maximum limit set by the clone.
Generally there is sufficient soil moisture in spring. Air temperature is the limiting factor. The optimum temperature for maximum cell division is around 17oC but ours is like a yoyo. Technically the king fruit has the best potential to be the biggest. But, do not be tempted to retain the king fruits. The bees may have done their job but since the king flower is the first to blossom, pollen growth may be too slow for effective pollination. Even when pollination is successful the low temperatures slow down cell division.
Assuming that we have pruned properly, once thinning is completed our supporting roles comes into full swing. Our actions can greatly influence cell size and intercellular spaces. Make sure there is sufficient soil moisture throughout the summer. Nutrients availability is influenced by soil reaction, salinity and nutrients balances. A pH of 6 to 7 is ideal and the EC reading is best when it is lower than 2dS m-1. Too much of one element may limit the availability of another. A good example is potassium. I know a member of our group who applied liberal amount of Muriate of Potash in late summer to harden his trees. It worked because the extra potash reduces the nitrogen uptake. However, after a few years he found all his trees were suffering from magnesium deficiency because the soil was too heavily loaded with potash.
One factor often overlooked by many is the rootstock. Among other things rootstock can greatly influence the apple size of some clones significantly. A good example I know is Sim Red. At CDCN apples are grafted onto open pollinated Columbia seedlings. Apples on one tree were consistently over 3” across while several trees besides it produced apples that were only slightly bigger than Heyer 12. I am sure some of you have observed the same phenomenon and I love to hear from you. Perhaps rootstock should be the topic of our next issue. If any reader is willing to take on this task, please tell me.
Forest Tent Caterpillars can completely defoliate the entire tree in a short period. This has a direct impact on the fruit size. Trunk Fireblight and canker take some time before they kill the entire branch. However in the meantime their presence causes unthrifty growth and results in smaller apples on the infected branch.
In a nutshell then, to get the biggest apple a particular clone is capable of, we must provide proper pruning, flower and fruit thinning, ensure proper soil pH and EC, optimum soil moisture and control pests and diseases.
This and That
An apple weighing in at 1.849 kg (4 lb 1 oz) on October 24 2005 is still the world’s record largest apple. It was grown by Chisato Iwasaki on his apple farm in Hirosaki City, Japan(1). The variety is Hokuto, a hybrid of two popular Japanese commercial apples, Fuji and Matsu. The record is almost 10 years old. Is anyone game at trying to break it? I do not know if Hokuto will grow here but if I were to attempt at an Alberta record, I would plant Elsie Wagner or Roppic. These are the largest I have seen at our annual fruit show since 1989.
Many of us peel apples before baking. Have you ever thought how long a continuous peel can you make? In 1976, Kathy Wafler Madison, at the tender age of 16, created the world's longest single continuous apple peel. It measured 172 feet, 4 inches long (2). That’s impressive when I could not go beyond three feet.
Research in England found that it takes 30 leaves to produce sufficient energy to grow one full size apple and still have sufficient food reserves to initiate next year’s flowers. Please bear in mind we do not have the growing climate England has and as such I think 30 leaves is a little low for us. The Japanese like big apples and most producers allow 50 leaves for the Japanese trade.
Thinking of making extra money? You might be able to if you are willing to go the extra mile. This year I saw 9 Fuji apples in a box with a price tag of $14.99. These were specifically meant as gifts for the Chinese New year on the 19th of February 2015. Each apple has the Chinese character for prosperity or good luck ‘written by the sun’. The price dropped to $9.88 on the 20th of February.
(1) http://guinnessrecordsworld.blogspot.ca/2011/05/heaviest-apple.html
(2) https://news.google.com/newspapers?nid=2209&dat=19771102&id=hn9jAAAAIBAJ&sjid=3HkNAAAAIBA J&pg=2321,213157&hl=en
Apple Maggot Solution 1
The following information was kindly provided by one of our Edmonton member Shannon. Thank you.
Please do encourage everyone to bag their apples to prevent apple maggot damage. I put on over 1000 ziploc sandwich bags last year and am still using up the last of my fruit. It doesn't take long, saves spraying and prevents so much waste. A few bagged fruits fell in the June fruit drop and a few of the last ones bagged were infested, but overall it was well worth the effort. Costco had the best price on bags. This was Thean's suggestion, so he may have some other ideas on the subject.
Bagging was done about the last two weeks of June. I did it as soon as the fruit was set. As this can vary by the year, a date is just a guide. A few traps will tell you when the bugs are flying, but by then you could be too late. This picture shows fruit in bags later in the season. Bagging does not seem to affect colour.
This second picture shows why you need to cut two little corners off the bags. Some people have asked about that, not remembering that apples respire and you will get a bag of water if there is no drainage. By the way, these holes do not seem to provide access for the insects. 2014 was my second year of bagging and there was no applesauce either year......another point some people have queried.
What I mean by "no applesauce" is there was no over-heating/cooking/mushing of apples in the bags, with no difference whether they were in full sun or part shade. The fruit came out just the same as in the pre-bug days--firm, crisp and juicy. Do emphasize that it takes a little time to thin and bag. I prepared 150 bags at a time (the contents of a box of sandwich bags) and stuffed them in one pocket of my apron. The other pocket received the thinnings. It took more time to select which ones to thin out and then to dump the contents of that pocket into the bin than to bag. Shannon
Bagging was done about the last two weeks of June. I did it as soon as the fruit was set. As this can vary by the year, a date is just a guide. A few traps will tell you when the bugs are flying, but by then you could be too late. This picture shows fruit in bags later in the season. Bagging does not seem to affect colour.
This second picture shows why you need to cut two little corners off the bags. Some people have asked about that, not remembering that apples respire and you will get a bag of water if there is no drainage. By the way, these holes do not seem to provide access for the insects. 2014 was my second year of bagging and there was no applesauce either year......another point some people have queried.
What I mean by "no applesauce" is there was no over-heating/cooking/mushing of apples in the bags, with no difference whether they were in full sun or part shade. The fruit came out just the same as in the pre-bug days--firm, crisp and juicy. Do emphasize that it takes a little time to thin and bag. I prepared 150 bags at a time (the contents of a box of sandwich bags) and stuffed them in one pocket of my apron. The other pocket received the thinnings. It took more time to select which ones to thin out and then to dump the contents of that pocket into the bin than to bag. Shannon
Pruning Workshop at Crop Diversification Centre
Here are some pictures of our pruning workshop on Saturday April 4th, 2015. It was a great learning experience for everyone. There are various pruning methods that were used. Thank you for all that participated and helped out.
This Season's Feature- Konrad's Orchard
Here are some educational information that I would like to share with our group. I am displaying Konrad's excellent pictures and information from past blogs. Just click on the link and read up on what great varieties of fruit, grafting techniques and ingenuity ( juicer creation) is possible.
http://forums.gardenweb.com/discussions/1448596/orchard-pictures-2013
http://forums.gardenweb.com/discussions/1888864/lets-talk-about-plum
http://forums.gardenweb.com/discussions/1503714/orchard-pictures-2012
http://forums.gardenweb.com/discussions/1512618/konrads-modified-bark-grafting
http://forums.gardenweb.com/discussions/1496639/my-juicer
http://forums.gardenweb.com/discussions/1888864/lets-talk-about-plum
http://forums.gardenweb.com/discussions/1503714/orchard-pictures-2012
http://forums.gardenweb.com/discussions/1512618/konrads-modified-bark-grafting
http://forums.gardenweb.com/discussions/1496639/my-juicer
DBG
Fruit Growers’ Bulletin 1-15 by Thean Pheh added Feb. 4, 2015
I know, I know the ground is still white and the season is still months away. But, it is definitely not too early nor too late to evaluate last year’s performance - what worked and what did not, what cultural practices can be improved on. What new fruits you want to add to or eliminate from your collection. This is also the time to contact other growers and friends about the possibilities of exchanging or buying scionwood. If the variety you want to acquire is a new release, please remember to check for Breeder’s Right. Catalogues from mail order nurseries are in and this is also the time to book varieties to avoid getting ‘Sorry, sold out’ reply.
Mark your calendar
We already know the dates for our two annual pilgrimages to the Botanic Garden and the pruning workshop at the Crop Diversification Centre North. (Just in case you forgot, Scionwood Exchange is on April 18th, our gathering for Fruit Show is on September 19th and the pruning workshop is on April 4th.) 18 people had expressed interest; 8 people out of the 18 have confirmed attendance and have been in contact with Jo. Thank you.
For those interested in buying, selling and exchanging old fashion heirloom vegetables and flowers, Seedy Sunday will be held on the 22nd day of March at the Community Hall on 118 Avenue and 92 Street. The event runs from 11 am to 4 pm. Admission to the event and attendance at any of the three presentations is free. Each presentation is one hour. I do not know what the presentations will be this year yet but I know I’ll be talking about zero tillage for home gardeners.
Thinning Apple
Fruit thinning is one of the essential chores in fruit production. Although it has been pegged down to the “T” and well known in favorable fruit growing areas of the world, on the prairie it is a guessing game and those who know are not saying much. What is written below is my personal opinion and what I have been practicing. I hope it is outrageous and contradicting enough to solicit and foster discussions and debates so that we can be enlightened. So please, please share your experiences and views.
Apples, pears, saskatoons, hawthorns, mountain ashes and black chokeberries are some of the pomes we grow. Pomes are extremely floriferous and productive. In apples, pears and saskatoons over production often results in biannual bearing. Two rounds of foliar application of complete water soluble fertilizers at flowering are sufficient to overcome this problem in saskatoons. Heavy fruit thinning is required for apples and pears. Even in commercial apple and pear orchards in more favorable fruit growing areas around the world, only 5% of the flowers are allowed to set fruits. Thinning can be done by hand or using chemicals. Cost of hand thinning is too prohibitive for commercial growers. Hence chemical means are employed after 5% of the flowers have blossomed. Essentially the chemicals prevent effective pollination to the remaining 95%. Chemical fruit thinning is not recommended in Alberta because of our unpredictable spring. Alberta Agriculture recommends fruit thinning after June-drop. Personally I find Alberta Agriculture’s recommendation is too late. Although known as June-drop, in the Edmonton area June-drop extends into the first week of July (mid July in some years. I have one clone that do not complete June-drop till the third week of July in most years). It is interesting and important to note that the potential size of apples and pears has already been determined by June-drop. (We’ll talk about this in the next issue.)
Immediately after flowering, all ovaries that are not pollinated will drop off. Those that remain continue to grow for three to four weeks before the tree drops more fruits. This is called June-drop. It is a self regulating mechanism for the trees so that they do not tax themselves excessively. Some clones are better at this than others. Goodland and Vick’s Pick are two examples of good self-thinner while September Ruby and Parkland are examples of cultivars that will not abort any pollinated fruit.
Many literatures call the bud at the tip of a spur of an apple or pear a floral bud. In realities it is either a vegetative or mixed bud. In spring if the bud produces only leaves then it is a vegetative bud. If it grows a few leaves before terminating in a cluster of flowers, then it is a mixed bud. To differentiate these leaves from regular leaves these leaves are called spur leaves. In theory the number and size of the spur leaves, and floral primodia had already been determined by around mid-July of last year. Energy for growth in spring comes directly from the little food reserves found in the bud. No matter how much food reserves there are they soon run out. The new growth then taps the greater reserves stored in the sapwood in the immediate area. Since many cultivars are only marginally hardy for our area, although the twigs are not winterkilled many of them suffer from winter damages to last year’s sapwood. (Undamaged year-old sapwood is white while brown indicates winterkill.) These hidden damages put another twist to the puzzle since damaged sapwood cannot pass on any of its nutrients that the spur required to supplement it limited reserve to develop newly formed spur leaves and flowers at the time supplies are most required. This means the amount of available food reserves in the spur and its immediate surrounding sapwood in spring has a direct effect on the number of flowers and how many spur leaves will develop, and how big they will be. The number and size of the spur leaves at this time are important because they determine the amount of food that can be generated not only to feed the developing pollinated ovaries (fruits) but also spur development and floral initiation for next year. The amount of sunlight the spur leaves received affects the vigor and amount of food that spur can produce. That’s why proper tree pruning and fruit thinning is essential for fruitful trees.
About the time of June-drop one or two buds grow at the axils of the spur leaves. These may produce one or several leaves before terminating in a vegetative or mixed bud resulting in short stubby contorted growth we call spurs. (In tip bearing types, for example Sunnybrook, the new growth elongates before terminating with a bud. Length of this elongation varies with plant vigor, age and cultivar.) Within metropolitan Edmonton all these activities, from bud break to next year’s bud growth, take place, by the end of June. In all trees, since fruits are given priority, the fruits are food sinks. Whether the new bud at the spur leaf axial is a vegetative or mixed bud is thus determined by the amount of leftover food by end of June to early July. Of course genetics of the cultivar also pays a part.
Based on the above observations, I do two rounds of thinning to aid the plants. The first is the removal of flowers and the second is the removal of fruits. Since I live in the city I remove flowers in May; some cultivars by the first week while others can only be thinned out after mid-May. I remove flowers after they have elongated long enough for me to pinch. The first to be removed are all flowers on all weak spurs. Since I thin all apples to 1.5x the diameter of the fruit, roughly 5 to 6” apart, I then proceed to remove all flowers from all spurs in between the spurs I have selected to bear fruit for the year. Since the selected spur contains 5 to 8 flowers but only one apple is allowed on that spur, my final step is to remove some and leave three flowers to a selected spur. I believe flower removal and thinning allow more food for the remaining flowers and pollinated ovaries to develop properly. Those spurs that were completely striped of flowers can use and concentrate more energy to develop next year’s crop instead of wasting it on fruits that will be eventually thinned out completely. Sometime in June (some by the first week others by mid-June) I proceed to thin out the fruits to one apple per spur. It is hard for beginners to tell which apple in the cluster had been pollinated at that stage. Even after years of observations, I do make mistakes. But then that is part of the thrill of growing apples and the prize to pay for lessons learned. At any rate if I have picked the right fruits (fully pollinated) to retain, I’ll get bigger fruits than normal: if I picked the poorly pollinated ones they turned out to be regular size or slightly smaller. What’s important is I eliminate the tree’s biannual fruiting habit and still end up with more fruits than my family could eat.
However, nothing is clear cut and there are always curve balls to handle. Some clones, like Rescue and Parkland, are strongly biennial and refused to grant me my wish. Drastic flower thinning and early fruit thinning have little or no effects on these cultivars on standard rootstocks. Perhaps there are some rootstocks that may induce these to drop their biannual fruiting habit. Since dwarfing rootstocks are more precocious I believe they might be my only solution.
This and That
From what little was printed in the “You Wrote” section last year, and talking with others over the years, I know many growers have more knowledge than I do. Instead of just me rattling away the little I know, please share; please feel free to contribute to this bulletin. You can either email your article to me or Jo. You do not have to stick to apples and pears; articles on other fruits and berries are also welcomed.
I know, I know the ground is still white and the season is still months away. But, it is definitely not too early nor too late to evaluate last year’s performance - what worked and what did not, what cultural practices can be improved on. What new fruits you want to add to or eliminate from your collection. This is also the time to contact other growers and friends about the possibilities of exchanging or buying scionwood. If the variety you want to acquire is a new release, please remember to check for Breeder’s Right. Catalogues from mail order nurseries are in and this is also the time to book varieties to avoid getting ‘Sorry, sold out’ reply.
Mark your calendar
We already know the dates for our two annual pilgrimages to the Botanic Garden and the pruning workshop at the Crop Diversification Centre North. (Just in case you forgot, Scionwood Exchange is on April 18th, our gathering for Fruit Show is on September 19th and the pruning workshop is on April 4th.) 18 people had expressed interest; 8 people out of the 18 have confirmed attendance and have been in contact with Jo. Thank you.
For those interested in buying, selling and exchanging old fashion heirloom vegetables and flowers, Seedy Sunday will be held on the 22nd day of March at the Community Hall on 118 Avenue and 92 Street. The event runs from 11 am to 4 pm. Admission to the event and attendance at any of the three presentations is free. Each presentation is one hour. I do not know what the presentations will be this year yet but I know I’ll be talking about zero tillage for home gardeners.
Thinning Apple
Fruit thinning is one of the essential chores in fruit production. Although it has been pegged down to the “T” and well known in favorable fruit growing areas of the world, on the prairie it is a guessing game and those who know are not saying much. What is written below is my personal opinion and what I have been practicing. I hope it is outrageous and contradicting enough to solicit and foster discussions and debates so that we can be enlightened. So please, please share your experiences and views.
Apples, pears, saskatoons, hawthorns, mountain ashes and black chokeberries are some of the pomes we grow. Pomes are extremely floriferous and productive. In apples, pears and saskatoons over production often results in biannual bearing. Two rounds of foliar application of complete water soluble fertilizers at flowering are sufficient to overcome this problem in saskatoons. Heavy fruit thinning is required for apples and pears. Even in commercial apple and pear orchards in more favorable fruit growing areas around the world, only 5% of the flowers are allowed to set fruits. Thinning can be done by hand or using chemicals. Cost of hand thinning is too prohibitive for commercial growers. Hence chemical means are employed after 5% of the flowers have blossomed. Essentially the chemicals prevent effective pollination to the remaining 95%. Chemical fruit thinning is not recommended in Alberta because of our unpredictable spring. Alberta Agriculture recommends fruit thinning after June-drop. Personally I find Alberta Agriculture’s recommendation is too late. Although known as June-drop, in the Edmonton area June-drop extends into the first week of July (mid July in some years. I have one clone that do not complete June-drop till the third week of July in most years). It is interesting and important to note that the potential size of apples and pears has already been determined by June-drop. (We’ll talk about this in the next issue.)
Immediately after flowering, all ovaries that are not pollinated will drop off. Those that remain continue to grow for three to four weeks before the tree drops more fruits. This is called June-drop. It is a self regulating mechanism for the trees so that they do not tax themselves excessively. Some clones are better at this than others. Goodland and Vick’s Pick are two examples of good self-thinner while September Ruby and Parkland are examples of cultivars that will not abort any pollinated fruit.
Many literatures call the bud at the tip of a spur of an apple or pear a floral bud. In realities it is either a vegetative or mixed bud. In spring if the bud produces only leaves then it is a vegetative bud. If it grows a few leaves before terminating in a cluster of flowers, then it is a mixed bud. To differentiate these leaves from regular leaves these leaves are called spur leaves. In theory the number and size of the spur leaves, and floral primodia had already been determined by around mid-July of last year. Energy for growth in spring comes directly from the little food reserves found in the bud. No matter how much food reserves there are they soon run out. The new growth then taps the greater reserves stored in the sapwood in the immediate area. Since many cultivars are only marginally hardy for our area, although the twigs are not winterkilled many of them suffer from winter damages to last year’s sapwood. (Undamaged year-old sapwood is white while brown indicates winterkill.) These hidden damages put another twist to the puzzle since damaged sapwood cannot pass on any of its nutrients that the spur required to supplement it limited reserve to develop newly formed spur leaves and flowers at the time supplies are most required. This means the amount of available food reserves in the spur and its immediate surrounding sapwood in spring has a direct effect on the number of flowers and how many spur leaves will develop, and how big they will be. The number and size of the spur leaves at this time are important because they determine the amount of food that can be generated not only to feed the developing pollinated ovaries (fruits) but also spur development and floral initiation for next year. The amount of sunlight the spur leaves received affects the vigor and amount of food that spur can produce. That’s why proper tree pruning and fruit thinning is essential for fruitful trees.
About the time of June-drop one or two buds grow at the axils of the spur leaves. These may produce one or several leaves before terminating in a vegetative or mixed bud resulting in short stubby contorted growth we call spurs. (In tip bearing types, for example Sunnybrook, the new growth elongates before terminating with a bud. Length of this elongation varies with plant vigor, age and cultivar.) Within metropolitan Edmonton all these activities, from bud break to next year’s bud growth, take place, by the end of June. In all trees, since fruits are given priority, the fruits are food sinks. Whether the new bud at the spur leaf axial is a vegetative or mixed bud is thus determined by the amount of leftover food by end of June to early July. Of course genetics of the cultivar also pays a part.
Based on the above observations, I do two rounds of thinning to aid the plants. The first is the removal of flowers and the second is the removal of fruits. Since I live in the city I remove flowers in May; some cultivars by the first week while others can only be thinned out after mid-May. I remove flowers after they have elongated long enough for me to pinch. The first to be removed are all flowers on all weak spurs. Since I thin all apples to 1.5x the diameter of the fruit, roughly 5 to 6” apart, I then proceed to remove all flowers from all spurs in between the spurs I have selected to bear fruit for the year. Since the selected spur contains 5 to 8 flowers but only one apple is allowed on that spur, my final step is to remove some and leave three flowers to a selected spur. I believe flower removal and thinning allow more food for the remaining flowers and pollinated ovaries to develop properly. Those spurs that were completely striped of flowers can use and concentrate more energy to develop next year’s crop instead of wasting it on fruits that will be eventually thinned out completely. Sometime in June (some by the first week others by mid-June) I proceed to thin out the fruits to one apple per spur. It is hard for beginners to tell which apple in the cluster had been pollinated at that stage. Even after years of observations, I do make mistakes. But then that is part of the thrill of growing apples and the prize to pay for lessons learned. At any rate if I have picked the right fruits (fully pollinated) to retain, I’ll get bigger fruits than normal: if I picked the poorly pollinated ones they turned out to be regular size or slightly smaller. What’s important is I eliminate the tree’s biannual fruiting habit and still end up with more fruits than my family could eat.
However, nothing is clear cut and there are always curve balls to handle. Some clones, like Rescue and Parkland, are strongly biennial and refused to grant me my wish. Drastic flower thinning and early fruit thinning have little or no effects on these cultivars on standard rootstocks. Perhaps there are some rootstocks that may induce these to drop their biannual fruiting habit. Since dwarfing rootstocks are more precocious I believe they might be my only solution.
This and That
From what little was printed in the “You Wrote” section last year, and talking with others over the years, I know many growers have more knowledge than I do. Instead of just me rattling away the little I know, please share; please feel free to contribute to this bulletin. You can either email your article to me or Jo. You do not have to stick to apples and pears; articles on other fruits and berries are also welcomed.