I have 50-odd varieties on several different rootstocks, (but mostly Ottawa-3 at present). A number of the older (10 - 12 years) trees have "runted out", (is that the correct terminology) - every bud on the tree has become a fruit bud. Over the past few years I have tried to stimulate vegetative growth by heading some of the vegetative growth, (dormant pruning), which, if I understand correctly should stimulate the buds just below the cut to sprout and make new wood. It didn't - the buds below the heading cut turned into fruits buds, so now I have trees covered in fruit spurs, but not an inch of new growth. (This sunk in to my consciousness when I tried to cut scion wood for my grafting workshop later this spring. There is nothing to cut.)
Now, a case can be made for this being a "good thing" - drawing from the espalier model, every fruit bud has at its base 5 leaves, which provides 5 times the photosynthetic potential of a single leaf bud. Is this complete nonsense?
Is there a case to be made for drastic, major surgery - cut the scaffold branches back to stubs, to provoke a flush of vegetative growth, a sort of catastrophic renewal pruning? (Presumably best done over more than one year...)
Broomholm OrchardZone 5b in Nova Scotia