Will Partial Defoliation Save this Wisteria?

Horticulture
1

I am assisting with a collection of mature bonsai.
The top 1/2 of a very old Wisteria wilted and lost all flowers and leaves from several branches a week to 10 days ago. Both the flowers and the leaves on the bottom branches remain healthy.
The wilted flowers and leaves have been removed but I’m hoping we can save these upper branches.
If we assume that 50% of the leaves have been removed from the entire canopy, do you think that partial defoliation of the lower branches (to 2/3s of the plant) would give this ancient beauty the stimulus required to rebud?
Should the surviving flowers be removed ASAP or allowed to wilt?
I apologize for not having pictures - I’ll get some in a few days.
Thank you for your thoughts.

2

I have super limited experience with wisteria, but I can provide what I’ve seen. Partial defoliation will push new shoots at the crotches of the old growth…that’s all lol. However, I’ve noticed that this will only happen with vigorous plants. I have one that was weaker than the other two that I have. Partial defoliation did very little for it. Some new shoots did push, but it was very sporadic and they were weak. Think of it this way; if the tree/vine is weak we shouldn’t be asking it to expend a bunch of energy pushing new shoots if it’s just maintaining what it currently has. Now add that on top of what your plant is showing which is signs of weakness.

My course of action would be to identify why the top behaved that way. Try to treat the cause instead of the symptom. In the meantime allow the foliage that is there to help rebuild resources. I could see a light defoliation as a means of energy distribution to ensure that the tree doesn’t just decide that the weaker areas aren’t worth saving. I can’t speak to that nuance though as I’m not familiar enough with wisteria.

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3

Any new shoots that appear due to partial defoliation will be weaker than the ones you just cut off. It’s probably in your best interest to do as @Bonsai_Bentley suggested, and figure out what is wrong with the tree and try to fix that. Other than that, it’s probably best to let it be and gather strength with the foliage it already put out.

4

Thank you for your comments. I also wondered about this distribution of energy.

I realize that the top reacted in a weak manner - but it was in full leaf and flower before it wilted. It may have been lack of water or some other dehydration - I suspect we may never know.

I think I may suggest taking the remaining flowers off with very light defoliation to see if we can spark some action.

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5

Seems reasonable to me