Repotting nursery stock into training pots

Horticulture
1

I have a number of new nursery trees in nursery pots, so have decided to repot them this spring (into training pots), to find the true base of the tree and the real nebari, then style them next year. I am doing this because there have been quite a few times I thought I found the true base of the tree in a nursery pot and styled it, only to find the real nebari further down on the repot, which would have been nice to know and suggested a different/better design. Also it’s nice to make sure the tree you are going to put all that effort into restyling has already made it through the repotting process.

My question is how much, if any, foliage to remove when I repot? I have heard Ryan say not to prune when you repot which makes total sense to hold onto as much solar energy producing foliage to grow new roots. (Although in the old days they said to remove the same amount of foliage as roots to keep the tree’s resources “in balance”.)

If I don’t remove any foliage, some of them will be pretty tall and wide for the training pot/colander, making them possibly top heavy and unstable. Also I’m wondering if left un-trimmed, the amount of foliage will be too much for the newly pruned root system to support.

Or, will all that foliage be a great help to growing new roots (assuming the plant makes it and survives). Or does it depend on the individual tree and species?

Or split the difference and trim them just enough to help stability but not enough to significantly decrease the photosynthesis energy?

Anybody else faced this?

Thanks in advance for any thoughts or advice.

2

It depends as does everything in bonsai. If you take off a lot of roots you will probably want to reduce the top some, so the roots are not stressed trying to keep the top hydrated. You may want to cut out a chunk of the top that will have no use in the future design. A possible downside of leaving everything is that the tree may decide that ugly trunk/branch is the one to keep so it discards the one you want. My experience is that commercial nursery stock roots are far from what we want for bonsai so there is quite a bit of reduction. Nursery stock from bonsai growers typically has better roots but will still need work. In addition to tying the roots into the new pot, I would also tie the top in if it is large compared to the pot - you don’t want any movement in the pot.

I would also suggest planning to wait at least two years before a major styling to allow full root recovery. If it grows well you can probably do some cut back this fall and next year as well as wiring of new shoots to start the styling, but I would wait two years for heavy cutback or wiring.

3

Thanks, that makes sense.