Quotes from the following 2024 article.
“While reviewing the pruning literature, I was amazed at how little research-based information existed on summer pruning.”
For apples " Since summer pruning was fairly expensive and had few benefits, summer pruning was not widely recommended."
For peach : “Summer pruning later than mid-July will have no effect on flower bud development. Removal of vigorous shoots that create shade can be performed about 14 to 10 days before harvest to increase fruit red color development for some varieties, but the increased color will be relatively small.”
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I avoid it here. The trees are already stressed by heat and wild moisture swings. No sense adding a new stress.
What the evidence proves is that summer pruning is pointless if you don’t know what your are doing, or your pruning crew doesn’t. It isn’t for commercial orchards-expert pruning is prohibitively expensive, but please explain how espalier apples sustain very high quality with rigorous summer pruning.
I have covered this a great deal on several topics so why not go there and question anything I posted that you feel the research contradiects? I really don’t want to start over. I will say that summer pruning at the beginning of summer is much different than summer prunng in the middle to the end of it if trees are vigorous enough to excessively shade leaves in the best location to feed fruit and next year’s flower buds. By then the leaves serving that fruit and the spurs has changed to ones much further away, and if you remove those step parents (vegetative shoots, mostly) the ideal leaves cannot return to duty- their photosynthetic powers will have been permanently destroyed by excessive shade. It will take too long for new leaves to form.
I doubt there is a professor in this country that knows more about the functional aspects of pruning fruit trees than I do, unless it is someone who is a very serious and studious hobbyist. The industry no longer performs finely tuned pruning and mostly never did. .
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@alan, I see some videos recommending late summer pruning when growth slows. Do you know of any advantage or disadvantage of late summer pruning?
I have summer pruned my apples and pears (young trees to encourage fruit spur development)… using the guys method in the youtube video above… and it worked nicely.
Again my goal was to get fruit spurs to develop on young trees.
My Novamac apple blooming last September after summer pruning early August.
Both of my young pear trees also bloomed last fall (for the first time after summer pruning)… and then again this spring.
I have apples ripening now on my 4 year old Novamac out in my orchard.. that I summer pruned last summer (early August).. and it bloomed in September… and then bloomed again this spring and set fruit.
For young trees that you want to encourage fruit spur development.. this definately works.
TNHunter
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I summer prune my trained trees (espalier and fan) and it makes a noticeable difference to fruit bud formation. But for open-centre free-standing trees I mostly leave them alone until winter. The context matters a lot, trained forms need summer pruning to stay productive and in shape, but on a standard tree you’re just creating more work and stress for minimal gain unless you’re specifically trying to let light into ripening fruit. TNHunter’s experience with young trees and spur development is interesting though, hadn’t tried it that way.
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I prune apple trees all summer long, as much as anything else so that I can manage to get all my orchards done before spring the following year, but I wouldn’t do it if there weren’t any advantages.
It is just as much how you prune as when you prune- you don’t want to remove shoots that are supporting fruit- as I said earlier, if the spur leaves and other leaves within about 8" of any given apple have been heavily shaded for several weeks then you don’t want to cut the vegetative shoots nearby, but it is generally helpful, as I understand it, to remove vigorous shoots emanating from bigger wood, like the scaffold branches themselves.
Removing vegetative wood that isn’t serving fruit benefits the shoots that are and it also reduces fungal pressure. One reason I summer prune is to open up the trees so I need about 40% less spray to get full coverage when spraying to control Marsoninna leaf blotch- and the ventilation and greater sun exposure helps on this as well. If the shoots holding the leaves serving fruit get more light they may give more sugar to the nearby fruit.
The reason centuries of anecdotal evidence that heavy summer pruning of espaliers helps produce high quality fruit is based on the important leaves to the fruit are never excessively starved for light between prunings because of the open design of the architecture.
The danger of late summer pruning is when the trees close up with dense vegetatiion by mid-spring so fruit becomes dependent on leaves farther and farther out in the tree. When you remove all the vegetative shoots the fruit will suffer because it takes too long for the tree to recover functional leaves near the fruit- the leaves there may look fine but their photosynthetic capacity may be vastly reduced.
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i mostly prune out new growth in the center of the tree and stuff growing towards the ground. i dont use shears just snap it off where it came out of the branch. easy peasy. lets more energy go into the crop instead of pushing useless new growth. works good here as disease pressure isnt as high as you guys further south.
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I was at a site today where the peach and nect crop was mostly destroyed by April’s wild temp swing and instead of a lot of energy going into fruit it was almost all going into rank vegetative growth. It would have been better to do the massive pruning I did there today a couple of weeks ago. So many orchards, so little time.
Out of about 20 different peach trees, only Saturn is holding a crop and it didn’t need pruning.