Field grown Trident


I started my bonsai journey 6 months ago, so I’m quite new to the bonsai world. I have read TONS of information and I gotta say: man, I wish I discovered Mirai live sooner. I have learned so much in the past weeks. OK, enough background story and on to my question:

1,5 month ago I went to a Bonsai nursery and bought my first field grown tree, a trident maple. I directly barerooted the tree, cut some of the big roots and put in a wooden trainingbox with 2/4 akadama, 1/4 pummice and 1/4 lava rock. That’s all I did. No pruning what so ever because I learned to strengthen the tree and establish the root system in the first year or so. OK, so now I have a dillema. Growing it for a year means March 2021, that’s the period buds will swell and break here in the Netherlands. So that’s not the time for some big structural pruning and branch cutting. I watch a lot of the fundamental video on Mirai and learned pruning a (trident) maple is best to be done after the leaves drop in fall (that’s around Oktober/November here.

So my dillema is:
Can I do the structural pruning this Oktober /November, considering I potted the tree begin March, without weakening the tree that much?
I need to add that the tree is producing leaves like crazy and looks healthy in my (beginner) opinion. I’m fertilizing with biogold.

This is the tree now


How structural is this planned pruning?

Mainly the thick, straight branches. The straight branch in the first corner from the bottom and about 4-5 thick ones in the top. Letting one leader grow. No cut in the actual trunk itself.

Hi @AaronVh you don’t have to decide now – watch it over the summer and make a decision according to it’s health and vigour. But generally, after 6 - 7 months of unimpeded growth (on a trident no less) I personally wouldn’t hesitate to do your autumn pruning.

Thank you for the advice. Yeah I was worried to get inverse taper on the upper portion of the tree, due to those thicker branches on top. That’s why I rather don’t want to wait till 2021 fall. But if I must, then I will. I’ll take your advice and see how the tree is doing at the end of summer.

Inverse won’t happen that quickly. I agree with @Ralph. Wait and see how it looks in the fall. Regardless, you’ll be able to make at least one of those cuts you mentioned unless the tree is declining.

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If you make a big cut in the fall:

  1. cut less than you’d like and respect the collar
  2. keep protected in the winter from winds and extreme cold to prevent dieback.

Having had trees die back from cold snaps you might want to wait until just before bud swell in the spring.

someone will have to fact check me, but I believe you can make a bigger cut when the tree is in summer dormancy as well.

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your tree will not add much to the root system after the fall. So you would not gain much here in the period till spring. So impact wise for the roots cutting in late fall is more or less the same as the following spring.
Agree to Eric. If you cut back prior to winter you loose “safety length” for winter dieback. So you need to protect the tree better.

I see that yours is on a balcony.

  • easy to provide the winter shelter
    maybe - , how much sun do you get during the day?

question for the forum. Deciduous normally would tolerate pruning and root work simultaneously better than conifers, shouldn’t they. If you would cut now, you invest the energy already in wanted growth.

I have around 4 hours of sun on the balcony. Later on this will shift to 5 hours. Not ideal, but it’s the only balcony I have. Winter protection isn’t a real problem. Got lots of coverage on the balcony…