I have been doing some summer pruning. Whilst studying up on the subject I came across this article that pretty much says summer pruning has no value except in very limited circumstances and the practice has no research backing it up.
https://extension.psu.edu/frui.....g-cautions
Based on this article I have decided to defer further pruning until the winter.
Zone 6a in the moraines of eastern Connecticut.
But there always had been proper research everywhere that summer pruning on young trees with yet a small root spread delays the maturity of the roots. So roots are barely talked about in the article but need to for the reason of making this following simple point.
It's well proven that summer pruning aids in the reduced size of the tree by reduction of the speed of root formation. Think of bonsai that are not grafted to any dwarfing rootstock. They consistently prune all year long so that the even more effort into the pruning of roots is reduced.
It's the upwards flow of hormones based on root size that determines tree size, and equally, the upper growth -the quicker the maturity of terminal growth is maintained there also more of a sustained command to the roots to spurt growth. A proper pruning class from the standpoint of bonsai and hormone flow is missing in your point of view?
I'm not so sure bonsai are good examples because they are extreme cases and bonsai dwarfing efforts are not limited to pruning. Besides selecting particular cultivars that lend themselves to bonsai they typically do not use more than a cup of actual soil and are often plopped on a rock (no offense intended to bonsai enthusiasts).
I do take your point that pruning limits root growth. If my trees were standards it might be worthwhile to summer prune but most of them are already on rootstocks so weak that the worry is they will fall over and die. As a matter of fact during storm Isaias last week my Nadia (on Citation) did actually blow over. Fortunately the trunk and main root were intact so I was able to right it and tie it back up. The flexibility of Citation roots is pretty interesting and, based on my experience with managing suckers, the same can be said for Newroot1.
Zone 6a in the moraines of eastern Connecticut.
I wonder what happens though that whenever late season lush top growth is permitted and during which the root growth is put in check, can the soil microbes and mycelium eventually make up the difference such as in "suppressive soils"?
I doubt that the cup full of soil in a bonsai container would be enough to permit an established kind of soil so in such an enclosed environment the check in root growth would be solely responsible. That and the amount of nutrients such as phosphorus that encourage roots.
Which gets you into nutrients, of which nitrogen is a promoter of lush top growth, as well as per part of your article the summer pruning does. So there are really two ways of checking root growth by considering nitrogen applications this time of year which will promote that lush top growth needed to try and put the roots in check. I do however understand that you will need to stake your trees.
Having said that about later nitrogen applications then you can still avoid a summer pruning by going with dormant pruning, although the soils are warm in the fall and the draw of mature top growth, although cooler, the roots remain warmer. Which means earlier you prune in the fall the better.
I think that part of the deal has to do with what you're growing and what the weather is like at certain parts of the year.
I prune cherries, plums, quince, and divide cactus in the summer, because it's dry and will limit the entrance of disease into the plant.
I imagine your cold, snowy winters would limit disease spreading. We don't really get snow in the WIllamette Valley. We have wet rainy springs, so I try not to prune much then, but I will move plants in rainy weather.
JOhn S
PDX OR
Yes John. If it were only possible here to move trees in a way to limit irrigation. Which really counts to slow the tree down after it's large enough to bear fruit. But point well taken. I'm obviously in deep thought thanks to Crankyankee so I found an interesting view and another suggested tool to use which makes the transition during the lush growing period look easier yet!
As in the previous links this video also seems to confirm keeping a check on root growth is what's being deployed here, but that's likely subjective to when in the year.
>> I think that part of the deal has to do with what you're growing and what the weather is like at certain parts of the year.
I think you are spot on about seasons and diseases, John. I realized watching some pruning videos from Raintree that their recommendation for summer pruning was based on exactly the opposite of our seasonal pressures. We are having a heck of a summer for fungus and pruning right now is asking for more.
>> Cinturing Explained
Rooney, that nursery in Kyogle NSW gets 41% more insolation than Vancouver, WA and 43% more insolation than Fairbanks, AK which means a tree there makes almost half again as much photosynthate as yours. Girdling a tree there is a far less risky proposition than for you:
Annual insolation, megajoules / year
Vancouver WA 4665 (1)
Fairbanks, AK 4599 (2)
Kyogle,NSW 6570 (3)
1. https://www.solarenergylocal.c.....vancouver/
2. https://energy.gov/sites/prod/.....-final.pdf
3. http://www.bom.gov.au/jsp/ncc/...../index.jsp
(convert kilowatts/sq meter to megajoules by multiplying by 3.6)
Zone 6a in the moraines of eastern Connecticut.
I'm interested now. But is that square meter being tied with insolation really a bigger shade footprint on the flat surface of the Earth than a meter?
I mean these are growing conditions from Fairbanks Alaska with motorized - automated energy collectors as students work there. So possibly this has been collecting the data you referred to?
BTW, Thanks! Never heard the term before.
I went through the data in the links you provided twice and could not prove the data between Vancouver WA and Fairbanks AK is real earth absorption. In planning fruit trees around Fairbanks we use regular size non-dwarfing apple rootstocks because the much cooler soils provide smaller trees than here. I hoped you survived Ida! 
>> I went through the data in the links you provided twice and could not prove the data between Vancouver WA and Fairbanks AK is real earth absorption.
You are over-thinking it. The insolation data are just empirical measurements of the total sunlight that reaches the ground. They are a reliable metric for comparing one place to another on a relative basis. My point in posting it was that you should be careful not to over-do girdling or maybe not do it at all because you might not get away with it like they do down under.
>> In planning fruit trees around Fairbanks we use regular size non-dwarfing apple rootstocks because the much cooler soils provide smaller trees than here.
Way back before the internet and before super-dwarfing rootstocks like M27 were available I got some advice on size control from a local pick-your-own grower. He told me to plant the roots very shallow and go light on feeding.
Zone 6a in the moraines of eastern Connecticut.
Crankyankee -- Please pardon my pitiful reply, but it is garnered from perhaps at least 40 years of reading a broad diversity of references -- some of which seemed to make sense to me biologically, and others which seemed to sound a little too much like perpetual horticultural lore. I also have my many years of observation under various conditions.
Truth is, I don't know for sure. However, I've come to the general conclusion that summertime pruning reduces the vigor of the top-growth (while also permitting "shaping" cuts), while winter-time pruning of dormant fruit trees does not limit the vigor for the dormant top, but may assist -- during the cool/cold dormant season -- in allowing the roots to grow a bit more than the dormant above-ground tree such that the root system is in a better position to make vigorous growth when the plant breaks dormancy.
Of course, both these realms of the winter-deciduous tree and the vigorously growing summer tree are thoroughly reliant upon the fertility of the soil and the access of the plant to appropriate elements of fertility available in the soil substrate. Plants are complex organisms. It is not enough to merely give them an N-P-K fertilizer (which is the conventional agricultural paradigm). An appropriate level of calcium is essential of course, but so too are the micronutrients that are so vital to healthy plants but are usually missing from people's yards and from commercially cultivated lands.
First, make sure that the calcium level and other macronutrients are at an appropriate level in the soil. Upon that important basis is the even more important crown of micronutrients. My personal preference is a mix of fish emulsion and kelp meal from a reliable, conscientious source. It can be amazing to see the difference in plant performance even from one day to the next.
Oh dear, oh dear, oh dear! I fear that I have strayed from the original subject. Oh naughty me!
P.S. Crankyankee: Hope you can get some of those Prunus maritima seeds. I have one tortured plant, several years' old but still alive. Self-incompatible so no fruit formation. But there is great pleasure in experimenting, learning, and ultimately succeeding.
Tim, thanks for the advice. I had a soil analysis done prior to planting my orchard and the calcium levels etc. looked ok but I do, as a routine, save and crush eggshells and spread them about. At planting I use the voodoo myco packs from Raintree. I don't know if they actually help but I don't want to risk the experiment to find out. I do use Agway 10-10-10 but so far haven't gone with an organic feed like fish or kelp so maybe I'll give that a try too.
So I did score a few tiny plants of dwarf Nana beach plum from Ken Asmus at Okios just before he closed up shop this past spring. Two of them made it through the summer barely surviving being browsed by deer continuously until I finally got a fence up. He also sent some seeds that I hope to germinate in the spring. Raintree has two varieties on offer now, btw.
Since I mentioned the deer here's the culprit. He appeared at noon out of the brush behind the neighbor's house where mama must have stashed him the night before which happened to be July 4. I figure she got spooked by the fireworks. He hung around in the center of the trees the entire afternoon while I was busy putting in fence posts. He sampled them all in succession but wouldn't try the bowl of water I put out. The next time I saw him was midnight about a week ago when I took the dog out for his walk. He and his sibling were in the front yard looking through the fence at the trees while mama and the other two siblings were in the back yard watching me watch them. If you've never seen a deer at night illuminated by a flashlight let me tell you it's an eerie sight because of the way the light reflects from their eyes.
Zone 6a in the moraines of eastern Connecticut.
Crankyankee,
Great picture! Beautiful fawn! It's just so sad that they grow up to be 4-legged locusts for those of us who want to grow particular plants without a quadruped gourmand about! Here in the boonies of southwest Washington, my wife and I have at least one local doe and whatever progeny she raises. A couple of years' ago it was twins. Just like the couple of "brush goats" that my wife and I had some years ago, the deer sure do seem to show the greatest preference for the plants that we most want to grow.
Years ago, I used to save and crush and use eggshells in the soil, or soilless mixes, for plants in pots. Within pots, I think that it can be of use as a long-term calcium source, but in the ground it may not be sufficient for something like a tree which -- during its growth -- will, I think, need a lot more soil calcium for the biomass that it will be producing as it grows.
As for the "voodoo mycopaks" [ 🙂 ] , I'm sure that there are many benefits to plants in regard to mycorrhizal associations with vascular plant root systems. However, given the diversity among plants, those that develop symbiotic relationships with particular taxa will tend to be one or few of a broad range of mycorrhizal symbionts. It would be good to get a fresh supply of a broad diversity of mycorrhizae for general mixing into the root zone of newly planted items. ...That being said... I was able to get a small bag of mycorrhizal spores with a broad spectrum of types, but I can't remember which catalog I got them from. ... I looked for the bag of them that I had, but it's been moved, and now I haven't a clue where it is.
One niggling problem that I have with my beloved wife is that she moves things in an effort to clean up and "organize", but when my stuff is moved I haven't a clue where it's been moved to. And neither does my wife. I had hoped to get the name of the mycorrhizal mix from the package [which location I once knew] to give you an option, but I guess that you'll have to resort to a Google search and try to find the product amid the relevant/irrelevant results that come in from the un-curated amalgamation of stuff that a Google search offers. My apologies, Crankyankee!
Reinettes
P.S. -- Don't know what your weather's been like back there, but ours has been absolutely whackadoo this summer!
Yes, deer do a lot of my summer pruning. It's not often what I want pruned, or bow I want it, but you can't get good help these days.
I summer prune fruit trees as other chores and weather permit. I respect the research that says it doesn't make much difference, but it helps me with timing. I try to let some fruits be shaded from sunburn, when possible.
I've concluded that it's better to prune some tree branches to reduce fruit load and branch length which bends the branches down to deer salad bar levels.
Reading the linked article (thank you crankyankee!) I do feel a little disillusioned, but his science looks decent. Of course, local conditions definitely apply and John your comments about disease prevention are well considered. I'm gradually moving towards human-sized trees in a highly fenced (cursed deer) situation, for accessible pruning, thinning, inspecting, picking. Some are espalier, which so far I'm pruning several times, summer and fall.
My goal is always to have a few bowls of good quality, good tasting, nice fruits throughout the growing seasons. Lately it's also to have a few batches of good fruits to can or make jam. I don't want or benefit from commercial orchard - volume production. Anyway, my home grown fruits are far better tasting than commercial orchard fruit at least from the grocery store.
I suppose that if the article is right that summer pruning doesn't limit size, then I can do it when convenient. With disease concerns during rainy season as a precaution, of course.
I suspect one can find an 'authoritative document' to support whatever stance one would wish to support.
The follow up posts brought good information as to effects on roots growth and the observations of weather considerations.
I find the referred to article itself to be disingenuous, at least misleading or misdirecting in its writing. I've been meaning to post something on this since first reading. Hope this doesn't on go too long.
It gets my goat, more than a bit, that folks evoke the name of Louis Lorette referring to the system of pruning based on his observations of his practice over an extensive period of time. From my experience, working from a very simplified set of instructions that I believed to be Lorette and had made my peace with my informal understanding of the biology at work, and come to terms of the rote mechanics necessary to accomplish my task, several times-several years, only then observing/realizing that further study was definitely going to be necessary.
The article author sites a published work by another author, of a work on dwarfed fruit trees, as his source and attribution to Lorette, for the methodology behind his dissertation experimentation. I do not know where the breakdown happened, but the description of of the experiment bears very little resemblance to my readings of Lorette.
The description as noted seems to me to be engineered to produce tons and tons of new growth. Oww where'd my apical hormones go? I need more! Perfect start to a plethora of scion wood if timed to survive the winter where you might be. Well that's scion/new growth on pomes, apples and pears, we know mostly, there's not likely going to be fruit on one year wood. That sort of pruning might be more beneficial on the stone fruit, where you are more likely to get fruit on the new growth. Either is going to be dependent on the fruit buds having the time to harden off before the cold weather damages them leaving only advantageous auxiliary vegetative buds to crowd the interior.
If the namedrop was meant only to add an air of legitimacy to the article well so be it... I intend to continue my experiments with summer pruning and trying to incorporate Lorettes observations as I can... methinks its a long study. It definitely lends one to observe the trees in their care in a different manner.
Cut to the chase. Go to the source, if you want Louis Lorette system of pruning, read Louis Lorette. Don't go with what some one said is LL, or what someone said someone else said was, and don't you dare go to YouTube and expect to get a footing. LL observed over decades; even apparently treated certain apples or pears some differently, I suppose having to do with vigor, French pear varieties I don't pretend to have any familiarity with.
I do not have care of any peaches, and so did stop reading LL when arriving at the chapter having to do with them. I suppose it's possible that chapter might contain information that might be more closely related to the described hand pruning carried out on the apple experiment, and was perhaps transposed.... I'm no expert, just a guess and I didn't come across the cited authors book to examine..
You'll be hard pressed to find a print copy of LL's work, but can read, if you've the time and gumption, from the digital library at Cornell University. Don't ignore the prefaces.
End rant.
I've been enjoying watching a couple of the UCSC YouTube presentations, specifically on the importance of summer pruning. Well, clearly presented. Posting links for part 1 and part 2 of 2 of the topic. Part 1 is 27 minutes long, the second is 11 minutes.The short one could serve to whet your appetite.
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