I have a couple fruit trees (Asian persimmon and European plum) I planted in the last couple years, and I’m now working on pruning a framework of scaffold limbs for these trees (I’m shooting for open vase for both species). Unfortunately, none of the trees are conforming to the lovely diagrams I’m seeing in various pruning articles. There are three main questions that keep coming up:
Is it a problem (and if so, what do I do) if one of the branches I’ve selected to be a scaffold is substantially different in diameter than the others? (e.g., 1/2" vs. 1"). Assuming there are no alternative branches currently suitable for being a scaffold.
Is it a problem (and if so what do I do) if the vertical spacing between the only suitable scaffolds is only ~2-3"? (All sources I’ve seen suggest substantially more than this – more like around 8-12", as I recall).
At what distance from the trunk should I head the scaffolds (if at all) to promote secondary branch development?
I’ve seen a couple bits of advice here and there, but nothing specifically related to persimmons or plums – I’d love to be a little more informed before I go out and do something foolish.
Anyway, any wisdom you care to offer on this topic would be much appreciated. Thank you!
If they are young you can prune the trunk down at knee height. It will push out multiple buds from there. I have one plum tree like this where the whorl of 4 branches is just about even vertically and it is pretty stable. Another plum tree they are 8-10” step-up with the top branch about waist high and it is also sturdy.
Another thing I have done on less ideally shaped trees from the nurseries is notch the bark above my desired branches and it routes the growth to that branch until the bark heals. Once the branches were thick I cut the central leader out.
Bottom line is don’t be afraid to be aggressive because if they are healthy they will recover.
Thanks, @jeremybyington for the data points on your plums. Yeah, they’re probably fine with either more or less vertical spacing between the scaffolds – I’ve definitely seen both in the neighborhood. I wonder if persimmons would also be okay with less spacing – I know they tend to be rather brittle trees; I’m worried about losing a scaffold in a heavy cropping year.
The distance between scaffolds is about fear of collecting ice, I believe. Supposedly when snow gathers at the meeting point of branches it can thaw and freeze and ice expansion and cause physical damage to the trees, but I believe it is repeated in the literature out of habit. When I became very serious about growing fruit 30 years ago i studied commercial orchards around me and most trees had scaffolds that violated this old rule. Also if 3 or 4 branches are more than half the diameter of the trunk and emanate from near the same spot on it they can stunt the central leader so it loses dominance. If you are planning to grow a tier above that point you would be out of luck.
As far as your oversized branch, this is what happens when you are not attentive from the very first season to the shape you are seeking. A commercial grower would likely cut it off, perhaps leaving a short stub to encourage a bud to form a new branch. If the tree ended up a 2-branch open center they might live with it. You have the time to repeatedly cut it back during the growing season so it may be best to work with it and try to stunt its growth until other scaffolds catch up, unless you are confident that a smaller existing branch can take its place. Plums tend not to be as cooperative as apples in allowing you to force branching wherever you need it by scoring the trunk. With young apple trees it is even safe to start over again and cut a trunk below existing branches because it will send out new shoots from older wood.
The problem with oversized scaffolds is that their diameter represents the amount of access they have to nutrients and water so they will fight you against submission to a less dominant role. However, they also need the energy from their leaves to stay in the fight and, if you are persistent, you can achieve balance.
Oversized branches also often outgrow surrounding tissue from the trunk that helps hold their weight, sometimes to the point of causing inverted tissue where it is attached there. Branches with inverted bark are the most likely to break and tear off the trunk when stressed with heavy crops or the weight of snow.
@alan, I really appreciate you weighing in here. I’ve been relying on extension articles until now, and - while they are extremely helpful and get me 95% of the way there - I find they often fail to convey critical overarching concepts, despite their abundant details. Right now, while I understand the basic rules and details of pruning, I’m still working on developing an understanding of how trees respond to pruning, especially from a resource-management perspective (i.e., how do I use pruning to strategically direct the tree to send its resources where I want it to). Your comments have made me think of pruning as an exercise in “channeling the flow of resources”, which I think will be a big step forward for me.
Anyhow, so if I understand you properly, with my trees with different-sized scaffolds, I could head the thicker scaffolds back and that might slow them down enough for the thinner scaffold to catch up?
Thanks also for the insight on vertical spacing of scaffolds. Indeed, I too only infrequently find a fruit tree anywhere around here that is “by the books” with regard to scaffold spacing. Interesting that it is related to ice accumulation. At any rate, because I’m only planning on a single tier open vase for these persimmons and plums (and I don’t need a second tier), I may just accept them as they are.
And thank you also for compiling and sharing your pruning guide – I had actually already read it through a while back and found it extremely helpful!
Just as you can keep an entire tree at a certain height with pruning you can control a scaffold. Spring and summer pruning is the key. Leave the smallest shoots and remove the vigorous ones at least 3 times during the growing season. The smaller shoots may grow fruit which will also help dwarf the branch. If the branch can be bent below horizontal it will also dwarf it as long as you go after the water sprouts this will encourage.