I am planning on redesigning the architecture of some of my trees
Some will entail removing major scaffolds (arms) from from my espaliers to allow some renewal and repositioning of the arms and some to permanently remove some arms and some to allow for grafting over next spring.
I am in Z5b and am wondering when is the best time to do that.
Should I do it now or wait until spring?
Because your goal is to renovate by removal and regrowth of branches, it would be somewhat better to wait until early spring before first growth. This is more invigorating than pruning when trees are in leaf. This is the literature on the matter and I have some anecdotal evidence that it is true. It is also logical that some of the energy from those leaves is going to the roots and big wood right now.
However, I have found that for big old apple trees, big wood pruning done in mid summer is less likely to lead to scorching of the bark. For your young trees I don’t think this will be an issue- at any rate, scorching tends to only weaken scaffolds in a way that may encourage breakage and your branches are supported. I don’t think I’ve ever seen even the most serious scorching kill a tree.
Unfortunately, I don’t have a lot of experience pruning big wood from espaliers although I have removed the top tier on occasion and regrown them. This is an essential procedure for espaliers or you end up with only the top tier being productive, I think, no matter how you manage the trees. The extra access to sun eventually seems to assure dominance, although with careful management, this could take a couple decades, depending on variety. The exact same issue arrives with all central leader trees kept to a height limit. The upper tier or tiers must be replaced in a rotation from old to new scaffolds or you end up with an umbrella tree. Not that this is a necessarily undesirable outcome for the amateur grower with free standing trees.
Thanx but as a follow-up…In re Japanese plums…
How old is the wood that they fruit on? When are the fruiting buds formed?
At what age does is become dead wood?
In the past I pruned , in summer, to either 1) short stubs or 2) after harvest I pruned off 2/3 of the current year’s growth. The result was an explosion of new shoots from the pruning site; I mean like a fountain of as many as 6-8 water shoots coming up from the point of pruning - all wanting to become trees - a jungle above the cut.
They fruit on both spurs 2-3 years old and on one year wood- but mostly the smaller wood. I don’t know anything about managing them as espaliers beyond just favoring small wood every time you prune. I never attempted the method you use of stubbing shoots back repeatedly on apples to force flower buds, because I don’t tend to sites with espaliers enough during the season although I do it on my own pear espaliers.
J. plums are not my preferred espalier species but I manage a few at a single site with fair success. The problem there is that I don’t make return trips during the summer and depend on the client to keep things in order. It took me quite a while to teach him how to favor small wood, which tends to work for all species I manage.
I have found d that ALL stone fruit more difficult to espalier as they
grow like weeds
Information on espalier stone fruit is very scarce.
Their advantage is that all varieties bare on last years wood so you don’t have to sweat developing spurs.