I have two NY9 prune trees that are about 5 years old and produced quite a good crop the last two years. I am happy about that but am baffled on how to control the new growth that they are producing each year. I have not fertilized them ever. They have been mulched each year and I apply wood ashes to all my trees once each winter.
How much of this new growth should be removed? Can I just trim off most of these new shoots while dormant and then do constant summer pruning to control the growth.
Would any of the trimmed shoots be suitable for grafting onto my Santa Rosa plum tree that is a dud for producing fruit.
I would say do not over do it! That tree is ok as long as sun can get to all fruit. Perhaps some limited thinning is in order and some topping of the taller branches to assure you can reach the fruit in future years. Another thing to think about since it appears it has good all round sun exposure is to begin tiring down to a more near horizontal growth orientation those older more mature scaffolds before they are too big and not easy to bend without breaking them.
If it were my tree I would do the tie downs first, then decide what to thin so that sun exposure can penetrate the canopy to all fruit producing limbs.
Since this is a European plum, it would not be the best choice for grafting onto your Asian plum as they are not able to cross pollinate, choose any number of other Asian plum, pluot varieties for that purpose.
In the first photo.Is that thicker branch near the center and then runs to the left,growing in the middle of the tree?That could be removed,if so.
Any inward growing or crossing growth can be cut out.
Also,things can be shortened by 1/3-1/2.
Pruning is the way to control size.
Wood ash does provide potassium,phosphorus,and magnesium,so that is a type of fertilizer.It’s about 0-1-3 (N-P-K).I understand though,what your meaning is.
It’s…hard for me to tell what all is going on in the picture, but I’d thin crossing branches, branches growing toward the center of the tree, and the branches that are going to shade each other out. Don’t take off more than ~1/3rd in one year.