When to trim this "tree"?
, thanks for the warning not to trim prunus in winter. Would it be all right to prune it the moment its leaves drop in autumn?
The usual advice from RHS etc is to prune them
when the sap is rising
so that it seals the cuts against infection from Silverleaf spores landing on them … ie prune from late spring to midsummer.
I never prune any prunus after the end of June.
Gardening in Central Norfolk on improved gritty moraine over chalk ... free-draining.
I agree with dove. Summer pruning won't premote the same boom in growth which is why I would do it over a few years so not to leave it bald. If you cut back a stem it will make it more bushy eventually but like mentioned above, these are trees and you will always be fighting it's instinct to reach for the sky.