Good day. I've got a pretty good idea about the "how" of pruning our neglected (prune) plum tree, but am getting conflicting advice about the "when". Some say June(!), some August and some during the dormant season. I'm in the W. Kootenays, +/- 1800 ft.. Plums have been harvested. Cool & wet now. Snow line is at about 3500 ft. (I plan to do the apple tree after the first hard frost & when the leaves are down.) Anyone out there have sound advice? Wait for hard frost? Leaves to fall? Spring? Thanks...
As long as you don't get winter killing of the branches, you can prune plum trees anytime. Supposedly, summer pruning is more appropriate for reducing the size of a mature tree; and winter pruning is better for shaping an immature tree. I prune all of my fruit trees year round and have never seen any negative effects. So prune whenever you feel like it or have the time.