Repotting timing question

I may have read this somewhere before, but can’t remember. Does this make sense?

Since the nutrients (energy) for the spring growth is stored in the roots, would it make sense to repot juvenile trees later, after bud swell (so the nutrients have time to get out of the roots before root pruning) and repot older mature trees earlier, before bud swell (before the roots release too much energy and create too coarse growth)?

Les Lonsdale

Personally i feel the timing of repot will always affect growth patterns. But I would not prescribe to the reasoning suggested above for regular care practices, or to manage growth.
I think it is safer to manage fertiliser amounts and timing, plus prune foliage or pluck needles. Thus controlling photosynthesis the source of energy for growth.

Thank you for that insight, Frank. Still, I am wondering (out of curiosity) if the hypothesis stated above is correct. It makes sense to me intuitively, but I’m not sure.

I will experiment on several trees this year to find out for myself, I guess.

I’d guess there’s more to the mechanics than that, but I don’t know enough to say one way or the other.

I have been scanning different blogs trying to get some insight.
So far the only advice on this topic that I’ve found is from Kaizen Bonsai. Graham warns against repotting too early, before bud swell. He says that it robs the tree of much needed energy for the coming year.
That seems to agree with my hypothesis, but wouldn’t that be desired in a mature tree, where you don’t want coarse growth, but only slight growth with small internodes/leaves?

I was thinking along the same lines - if we’re pruning to manage vigor, wouldn’t that be a good thing?

As with many other techniques, it can be helpful to evaluate results in terms of the desired goals (e.g. increase or decrease vigor).

Some time back I printed this from the internet, and now I cannot find it again so here is a scan

It gave me a lot of insight into what part of a tree grows when. I start repotting in January and put the reported trees on bottom heat (78 F)in an unheated hoop house. The roots experience spring and summer while the tops are still mainly doroment. BTW I am in Charlotte NC zone 7/8. Hope this helps


Cool chart - it makes me wonder how the pattern applies to different species and different climates. Thanks for sharing it!