Apical Dominance and Control During Development

Beginners
#1

Apical Dominance and Control During Development

Background
G’day everyone. I am currently developing a bald cypress in Australia (late Summer) where it will not stop pushing new apical growth and I am unsure on what to do. It was repotted end of winter and heavily pruned early spring. It pushed out quickly and in early Summer I was able to prune again and get another big push extremely quickly.

I have been pinching buds and removing new shoots when I can, to stop growth in areas I do not want however not enough attention was paid and the apical region has taken over tremendously and has largely impeded the growth of the lower foliage. The tree is still producing a lot of new growth all over and both upper and lower foliage/branching is budding.

Temperatures never reach below 10C /50F (typically 25C-30C 77F-86F) even in winter, and currently in development on primary and secondary structure.

Concern
I do not want to waste this energy the tree is putting into new foliage at the apex and would rather it be redirected to the lower branches I want to develop.

Questions

  • Should I prune all the apex growth I do not want, or do I need to wait for early Spring?
  • Is there a way to avoid the problem I have or a method to maintaining growth I should consider?

My thinking thus far

  • I should not prune now (end of summer) as this will weaken the tree with a tremendous loss of energy and no return for its efforts. If I do, I should wait several weeks once hardened to allow energy to be regained.
  • When I first saw a lot of new growth at the apex, I thought I should let it grow to gather energy and it will harden soon and later removed, however it is still growing strong.

There is clearly a gap in my understanding, and I would like to know or be pointed towards what I am missing.

#2

Are you trying to develop the tree or refine it? What size pot and what substrate are you using?

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#3

I would wait until late winter/early spring to prune the apical growth. I would prune it fairly hard it the apical area is thick enough. That should direct the energy into the lower branches. If the apical area is out of control before going into winter storage, you can prune it back some, but leave the branches a bit long to allow for winter die back. Bald Cypress is a very apically dominant species so you may have to get it into bonsai soil better designed for refinement before you can get the apex to slow down, but that will also slow down the lower branches.

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#4

Developing primary and secondary branching still. Pot size about 55cm x 35cm x 10cm oval, the tree has three trunks.
I bought the soil premade but it seems:

  • Potting Compost: ~30-40%
  • Pumice: ~33%
  • Grit: 33%

The lower branching does have a lot of growing to do and my thinking now is that I may have be continuously pruning the apex (like every week) during spring/summer, then once thats done transition to apical development?

#5

Thanks Marty that makes sense to me. Would I be wrong in thinking after I prune the apex hard next spring, I could watch the growth continuously and remove any apical budding during spring/summer to maximize energy to the lower branches? Or is this a good way to kill a tree haha

#6

The in season budding/growth you see on bald cypress are really just leaves and can generally be pinched back fairly strongly. They may lignify into branches, but that normally requires allowing them to extend or at least have enough time to push out new leaves from along the stems. I have found that pinching the growth back to a couple of cm after allowing it to extend to 5 cm or so does not seem to have an adverse impact on health of the apex although it may not lead to optimal ramification.

#7

@Brodie
Some included pictures always helps!

Is there a way that you could lop off the apex and let one reestablish by a branch a little lower?

I was thinking that maybe you need to transition to “proper bonsai soil” asap as this soil slows down growth and helps ramification. Organic soils will increase growth.

Overall I would be concerned too about cutting off so much so often. I would caution to pinch and let foliage harden off before cutting back for sure.

Can you house the tree in a less sunny area?