Defoliating top of JM to increase growth on lower branches

[L-12]

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

 

[MrWunderful]

Yes.

But it ultimately depends on the health of the tree.

 

[Dav4]

Let's see some pictures. I'd be more inclined to cut back the vigorous branching up top plus minus removing some of the foliage and allow the bottom branching to grow unhindered.

 

[Deep Sea Diver]

Interesting. Do you need to totally defoliate the top of the tree? It should work if the tree is really healthy, however, what would be the issue with a stepped partial defoliation?
Assuming the tree is healthy and the leaves have hardened off, you could cut back to two leaves on the outside branches like normal leaving the petiole stub, then if you need even more light, cut off one of the remaining outer leaves (the topmost one of the two). If that still doesn’t suit you can cut the remaining outer leaf in 1/2. I do it along both edges of the leaf so the result still looks good. You can do this all over the tree if you desire to get max light penetration.
This provides one with options along the way to assess light penetration to the interior leaves and branches.
(btw: I adopted this idea from Bjorn Bjorholm BE intermediate course where a Japanese master demoed this and it seems to work really well on my JM cultivars. I used the Peter Adams partial defoliation method before. I’m seeing better results using this method. We’ll know more in a couple years!
Good luck and Cheers
DSD sends

 

[River's Edge]

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

Defoliation is not used for the purpose you have in mind. If you wish to strengthen the lower branches cut back the top somewhat and make sure they are not shaded out by the vigorous top!
Leaving a small number of leaves to support the tree is the wrong way to go, unless you wish to seriously weaken the tree!

 

[Deep Sea Diver]

Defoliation is not used for the purpose you have in mind. If you wish to strengthen the lower branches cut back the top somewhat and make sure they are not shaded out by the vigorous top!
Leaving a small number of leaves to support the tree is the wrong way to go, unless you wish to seriously weaken the tree!

Agreed. The technique‘s main purpose, which I described above, is not directed to make smaller leaves etc, although it certainly ought to, it is specifically designed to give the weaker inner branches more light so that the inner core branches of the tree are strengthened each year. This will give one more options when trying to push the form back into shape.
cheers
DSD sends

 

[L-12]

Thank you so much! I have already removed one leaf from each pair of leaves on the top, but it is still dense enough to be shading the lower branches. I like the idea of cutting the remaining leaves down.
Thanks,
L-12

 

[Deep Sea Diver]

You are welcome. I find trimming back Just the outer leaves and any “stray” inner ones usually does the trick. From here on I cut just the big ones off until things get balanced.

Also, another thought... If you haven’t already been acquainted with Walter Pall’s hedge trimming method for prerefinement maples, it would be good to at least check his ideas out, so you can broaden your bag of tricks.

Cheers
DSD sends

 

[Lazylightningny]

Pictures please! We need to know what stage of development this tree is in in order to give better advice.

 

[Deep Sea Diver]

Yep, that would be very helpful, esp in light of your report about thread graft failure

 

[erich_raudebaugh]

I partially defoliate maples that are very vigorous and in refinement or getting close to refinement. If you don't, you will shade out weak interior buds and branches and they will die or weaken.
I've totally defoliated Japanese maples and never had any problems, but this can only be done on very strong and vigorous trees, do not attempt this if you have any doubt at all. Also I've been in the hobby for 30 years, and I'm pretty confident with maples.

Do some research on partial defoliation, it seems like that will do the trick, but we do need to see pictures!

I also live in Beaverton, maples love it here.

 

[sorce]

Aye.

I don't think defoliation is your answer either.

Since this will inevitably produce more growing tips up top as well.

You are essentially just slowing down the top in order for it to gain 2 times the speed. Winning a battle, losing the war.

Cutting it back so there are only 2-6 growing tips at all up top...which can be defoliated to a degree later, is how you win the battle and the war.

Sorce

 

[River's Edge]

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.

 

[Forsoothe!]

Partial defoliation may or may not solve this problem short term, but doesn't address what happens next. Post #25 speaks to balancing growth of lower layers long term, which is also a function of design. The problem in this post is that the style/design is incompatible with life. You need to alter the layers, especially the top, and maintain the design within the limits of the leaf surface area requirements. This post is an illustartion why hedges running east-west have a really nice south side with the north side that is thin and hollow.