Not saying you are wrong, cause I don’t know. But one has to be careful to assume a correlation from those one time anecdotal observations. The infection might had happened coincidental after your pruning.
I do my major pruning in very late winter or spring. In summer I only do minor pruning as removing watersprouts and such. I try to avoid removing a lot of leaves in summer. That way I try to get the best from both worlds (winter pruning versus summer pruning).
Calvin,
Besides reading articles/info sheets from university’s extension services, I listen to advice from experienced forum members particularly @Olpea has he has a peach orchard and has shared his experienced with us consistently.
Like @carot said, the canker and the summer pruning your experience could possibly be a coincidence. However, in the end, it’s your choice to do what you think is best for your peach trees.
I agree, and to hold it above what experts say is usually not a good idea. I have only heard of infections caused by winter pruning on sweet cherries. Also apricots, but other trees I agree it’s the best time. Summer pruning that I do is light to stop vigor and control height.
I do think that late summer pruning is probably not a good idea.
Here in Michigan one of our biggest crops is cherries and Michigan State University says the best time to prune sweet cherries is around August 1st. So that is when i do most of my sweet cherry pruning. OSU and other universities work with them too. I prefer to follow their advice. The financial lives of commercial orchards depend on their advice. They do not make statements that are not well founded in research… One must decide for themselves whose advise they wish to follow.
I concur. If you make your decision for a well-founded reason thats the best you can do. My goal in posting those articles was to make clear that right now it seems there is no simple and always right answer to the question when is the best time to prune fruit trees (or trees in general). Oversimplifing is dangerous cause there still are surprisingly many questions to examine.
As the arborist in that articles states, to his surprise many experts don’t consider the fact you are hurting the trees ability to store reserves for winter when doing substantial and late summer pruning. The fact itself is known but it seems it is ruled out as a major problem without any scientific proof to be neglectable. From his experience it is not and needs to be considered. If other factors are a pro for summer pruning (eg. disease pressure in winter time) they of course need to be considered too and in some cases it might be best practice to only do summer pruning. But it isn’t a general rule for every situation or even most situations.
Silver disease is the problem with cherries, although peaches can get it too.
Canker is more related to how a tree branches. If you use a bad crotch angle, the bark does not grow right and can grow into tree. Here is where canker reins. So choosing bad branches to keep has it’s consequences. If you make structure correct from the start, you will avoid problems down the road. Timing is important too.
I myself have summer pruned for 7 years now, and it works great for me. I have no plans to stop. I live in a cold zone and my trees are doing great. I do think winter pruning is essential too. For me to manage trees properly I need to prune summer and winter. At least when young. That could always change as my trees are more mature now. My trees this year seem slow to grow, so no summer pruning this year as i want to encourage vigor at this point.It’s too wet for them, environmental stress. Peaches seem to hate it most. I may prune plums and cherries, see when it’s time…
Lot’s of good comments here.
I used to prune “when the knife was sharp”. We still do some, for labor cosidrrations. But it’s best to prune peaches in warmer weather during the growing season.
Here’s a peach tree we pruned a few days ago.
Here’s one we pruned back to nothing a month ago.
We go through and rip out those upright shoots about this time. We don’t head them, we rip them out.
The caveat is that if it’s varieties which tend to produce a lot of blind wood, like Earlystar, we might head some back.
Honestly I can tear off an amazing amount of wood without pruners. Green wood is easy, but if you are agreesive, you can even tear off year old wood. It makes an ugly wound, but there is no downside to being rough with vigorous peach trees during the growing season. To put it bluntly, don’t pussy foot around. You can’t hardly hurt a vigorous peach tree during the growing season.
Vigorous peach trees are more weed than tree.
Richard Harris is or was a professor emeritus at UC Davis and his book is based on careful research by many scientists, including studying pruning wounds and measuring the speed of healing and comparing the results of pruning at different seasons.
There has been a great deal of research on this subject, actually, partially because it isn’t terribly complicated or expensive to do- to measure how long it takes the wounds to close.
What is complicated is variations of climate and species, but the conjecture of a single man who hasn’t even performed research, let alone include the research of other scientists is not very conclusive to me.
I have witnessed the results of apple trees cut to nothing but huge stubs next to the trunk that could barely recover a fraction of the foliage after an entire season of growth that was lost- and yet ten years later are larger than when they were completely butchered. .
This is the kind of thing people do who inherit trees on a property they only bought for the house.
A weak tree is easy to kill, but a strong one can be very hard to kill- even when you cut it to the ground.
Sometimes we get a snow here in early fall and the tops of trees snap so violently it is like a war zone. Huge wounds are torn into the trees and major parts of their canopies are lost, and yet they almost all survive the abuse.
I hear stories of orchards in hurricanes where the entire canopy is blown off trees in late summer, and the trees survive.
When Drew talks about pruning cherry trees in the summer, he’s talking about what commercial growers do to thousands of trees that their livings depend on. The trees on Mazzard require aggressive cutting- year after year- in summer.
If this was damaging to their survival it would be well known by now.
However, everyone puts very high value on their own anecdotal experience, even though correlations can often be coincidental, even multiple times and even when there is a very logical explanation of why the relationship could exist.
Researchers do exactly the same thing with their research, of course, but they have more data, which presumably makes it more difficult to be tricked by coincidence, but there are always logical leaps involved with interpreting research, and those leaps can land you on mistaken conclusions. This tends to make the public even more trusting of their own anecdotes when they hear repeatedly of research that contradicts previous research.
I think a lot of what is going on here is well above me. I was just sharing my experience. It could most certainly be coincidence that both my trees got canker after summer pruning. Maybe it is a local environmental risk factor for canker…or…maybe not. Anyway, it was enough for me to come to my own opinion on summer pruning of stone fruits. Pome fruits on the other hand, never had any problems with some summer snipping.
I’ve given a few peach trees canker by summer pruning, but that was when it was middle of July and pruned them hard enough it sunburned scaffolds. When pruning in the hottest, sunniest months, we leave a little more foliage in the middle of the tree to shade the scaffolds. Since I started doing that, I don’t get any sunburn, which turns into canker.
In terms of peach trees, fungal canker grows mostly during the dormant season. Canker can grow at temps lower than the peach wood can grow. In fact, canker grows best when the peach wood isn’t growing. Canker stops growing when temps get hot, which is when the wood really starts callusing.
That’s why it’s generally safest to prune in hot weather during the growing season. Of course pruning late in the growing season has it’s own set of problems, as mentioned by others.
I’m not discounting your experience at all. I’m just mentioning what I’ve read over the years, which matches what I’ve seen.
All that said, there are many times we prune just about any time of the year, at times when we have time. I just prefer to do most pruning during the growing season, if we have the labor. Plus, most of the time we have to prune during the growing season, or we get too much shade. That’s the kind of pruning I mentioned where we rip the new green shoots out by hand.
Do you find any difference between bacterial canker and fungal canker in regards to what you mentioned above with temperatures and canker growth? Just wondering, my trees had bacterial.
It’s interesting how in apples the general consensus is that it is sun exposed bark that is the problem, but I think it has more to do with simply reducing the flow of sap when you reduce the amount of canopy, if the sap is moving rapidly through transpiration it wont get super heated even when bark is exposed.
This is something that actually hasn’t been researched to my knowledge. All I know is that it seems bark can be fully exposed to hot sun and not damaged as long is there is adequate foliage pulling sap. But shade also is going to reduce the temperature of the cambium (actually, I believe that is what is being damaged- the bark is mostly dead).
Most of the canker I have dealt with is the perennial (fungal) kind. It’s pretty easy to recognize. It’s an ongoing yearly battle between the tree and the canker at the canker site (hence the word perennial) . It seems in many locations, the trees eventually succumb to the canker. It doesn’t happen so much here. The vigor of the trees generally keeps the canker from spreading enough to girdle.
I do have some relatively sudden dieback of scaffolds which I suspect could be bacterial canker, though I’ve not verified it. It acts like bacterial canker in that it’s fairly sudden, and tends to stop as temps warm up, but I haven’t really seen much gummosis, which is associated with bacterial canker, although I haven’t really looked hard for the sap. When an occasional scaffold dies, we just cut it off and move on.
Like fungal canker, bacterial canker is considered a “cold” weather disease.
I think my little Red Haven is looking quite promising. Would love any constructive advice - as to pruning. I have this Red Haven and a ‘revived from the dead’ Indian Free. I thought it was dead, but cut it way back - and it ‘came back’ . . . although VERY short! LOL I also have a Mericrest Nectarine and a Harko. Only the Red Haven has fruit. This is the second season for all.
I am having a hard time with my apples. ? I just don’t know how to prune them, and need some advice. I read the ‘diagrams’ and just can’t ‘get it’. I tend to want to do the ‘open vase’ thing on just about everything . . . Can’t seem to get the hang of the modified central leader, etc. Any advice? I’ll post the pics I have. Thanks.
I have apples planted all along the back of my pomegranate ‘orchard’. The Pink Lady seems to be doing well. I also have a Goldrush. A Mutsu. And an Ashmead’s Kernel. Same pruning ‘problem’ with all of them. Lots of scaffold branches - and don’t know what to get rid of!
Just found Richard Harris’ Arobriculture 2nd edition for 2.70. Looking forward to the read.
PomGranny,
Your Indian Free is on the way to your scaffold selection, think positive! Often our country stores have fruit trees for sale, but they are way to tall/developed to have good scaffold potential. I like small trees with good branching down low. .Peach trees grow so fast
Should I lop off the tops of my apples ‘at some point’ soon?
In late winter? Sooner?
I read here, that summer pruning is preferable . . . but that is a drastic ‘lop’!
They are all quite tall. Some reaching over 5 feet. I will get out the old ‘modified central leader’ tutorial again - and see if I can ‘get it’ this time.
I am not at home, at the moment . . . but I should take shots of, and post the other apple trees. They are not pruned much, yet . . . and would demo what I am talking about much better. I will take more pics and get the forum’s feedback. Thanks.
You can use notching to get scaffolds down lower on the tree. You will still need to remove some of the existing upper branches to redirect some of the vigor to the notched buds / branches, but you wont have to do a severe heading cut.
I would also do more limb spreading, it will give you a lower branch structure and possibly more fruit on those branches.
Hi Alan,
it sounds lilke Richard Harris’s book would be very interesting lecture. At the moment it is not available for me for a price I am willing to pay. The cheapest I found is Euro 164,00 for a used paperback version…
If possible could you please sum up in a short note what he found out about best pruning time? Does he advocate (late) summer pruning even when doing substantial pruning or at least found out it is without detrimental effects for a tree (even a weaker tree)?
From what you wrote before I would suspect that single man conjectures are not that far from what Prof. Harris might have observed about pruning effects (not only wounding). And in principle he agrees with what Drew adviced too. He just warns to do substantial pruning in late summer. Wound healing is still better then than in winter time. But a tree is weakened by this practise (his opinion). Depending on the condition of the tree that might be decisive. In professional recommendations for arborists here summer pruning is advocated as the best time for pruning. That includes late summer pruning of very old trees. He advises against that practise. I found that to be comprehensible. Maybe that is overcautious?
I myself have not seen this happen. Not saying he’s wrong. I just have not observed any problems like this in 7 years. I won’t prune after August 1st usually though. That gives my trees 2,5 to 3 months to prep for dormant season. I still harvest figs here in early November. I guess I don’t consider my practice as late pruning.
We do know pruning can stimulate growth and lowers hardiness some, so it makes sense not to prune late. I have had no ill effects by stopping pruning the first week of August. Seems trees have plenty of time to prep for winter.
Very helpful pictures of your summer peach pruning! I rip my upright shoots out too when I have time, but not as much as you do. Probably about a bushel or a huge armful of shoots per tree. From what I understand its standard practice for peach orchard in my area.
