I have a Japanese Maple that has vigorous growth at the very top. I tried several thread grafts to the lower trunk, only 1 graft survived. Now I see a couple of new branches emerging from the lower trunk. I understand that you can kill a JM with complete defoliation, unlike a Trident which can be defoliated without any trouble. My question is:
Can I defoliate the vigorous top, which would leave a small number of leaves on the thin new branches lower on the trunk? Or would that kill the tree? Would the lower branches thicken if left alone?
Thanks,
Beaverton OR
A picture would be very helpful.
However, your comments clearly indicate a tree in development. desiring lower branch structure and increased density in the lower portion of the tree! The fact that you are thread grafting lower branches and have weak lower branches with few leaves indicates a long way to go before refinement.
Defoliation is not useful for this purpose! It is a gentler technique used in refinement to create small adjustments.
It can create a new second growth of smaller leaves. It can create an increase in the number of fine shoots. The leaf size will reduce. Balances stronger and weaker parts. ( small adjustments) Used to replace damaged leaves. Often creates a more vivid fall coloration.
And can be used for aiding a deciduous tree when transplanting out of season.
The technique you choose should be based on the condition of your tree, the stage it is at, and the response you are looking for.
If you wish bud back, additional branching lower down then cut back the top in accordance with the condition of the tree and the stage of development.
Make sure the light gets in to the lower part of the tree ( prune unnecessary branches or wire open ) and rotate to expose all sides to the sun during the growing season.
The lower branches will only thicken if not shaded out! They will thicken faster if the top is cut back. New buds, thus new shoots lower down will be created from cutting back the vigorous top.