Hi All,
I’m just looking for some clarification on a comment Ryan made during the recent Linden styling stream. He mentioned during the stream, that when starting deciduous nursery stock to ensure that most of the native soil is removed and replaced with an arable bonsai matrix (akadama). He has also always reinforced the importance of a strong healthy root system before starting any major work, and when re-potting, to leave a lot of foliage for the roots to recover. The linden in the stream came from the nursery in a burlap root ball with a trunk girth of about 3.5 to 4 inches, so it must have been at least 12 to 15 tall.
So was the initial root reduction and re-pot done as a whole un-chopped 12-15 foot tall tree, with those fairly large trunk chops done a few years later? Or do you think there was a “reasonable” height reduction made during the initial repot?
This pomegranate stream shows the initial repotting of a deciduous field grown tree. I think he mentions that this is the video to watch if you are interested in learning about initial deciduous repotting.
https://live.bonsaimirai.com/library/video/pomegranate-design
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My guess is that it was chopped in the ground to something more manageable before it was balled an burlapped. Ryan commented it had been grown for bonsai which is why I am thinking that. The key is to leave plenty of foliage for root regeneration. If the roots are reduced a huge amount, plenty of foliage may include a fair reduction of the trunk and heavy branches. Having all of the foliage may even be too much for the greatly reduced roots to supply and cause foliage dieback.
One the other hand with very young material (2-4 year old seedlings), I leave all of the foliage and let the tree eliminate the foliage it cannot support. I even did this with a batch of bare root trident maples that I got in full leaf (placed my order late). I reduced the roots by about 50% to get them into reasonable grow pot and in most cases only the tips of the 2 ft. (60 cm) tall whips died.
I think there are some misunderstandings here.
Leaving enough foliage on the tree for root regeneration refers to conifers and is not applicable with deciduous.
If you are repotting a deciduous tree and there is foliage on the tree then you are repotting too late and have missed your window. You may get away with it, but it’s not good practice and does not make sense in the long term.
If you have a large deciduous tree in a large container or in the ground that you want to get into a smaller container I don’t really see an issue with cutting back and repotting as long as the buds have not started to push out.
Best,
Ryan
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Ryan - I think that you need to leave a fair number of good buds on deciduous material to push easy foliage to help drive root growth after a major cut back. I believe that if you are counting on the tree to push adventitious buds as well as new roots roots you are asking for trouble, even on a tree that buds back easily. That is why the general advice is to only do one major thing per year/season.
Okay, awesome, that makes sense… for a large nursery deciduous in early spring it’s pretty safe to go ahead and reduce the height of the tree prior to initial repotting but just make sure there are a lot of buds that can push easily. Then let it “cook” for a year or two to regenerate, then start styling.
I’m going to re-watch the pomegranate stream today. It also looks like the trees in the streams kind of resemble bushes to start with, rather than the typical tall standard type landscape trees. Will have to keep an eye out for those when visiting the nurseries.
It amazing how much more detail you can pick up by re-watching the streams. I think I’ve watched each of the Thuja steams 3 or 4 times now.
Just finished the pomegranate 2018 stream. Wow can’t believe I forgot all that. Explained everything about taking a large raw deciduous tree, and doing a major initial styling and repot. Excellent stream that everyone should re-watch. 
It’s packed full of knowledge. I think I’ve watched it three times already and I think it’s time for another.
Hallo, if you want to see more about the linden, watch nursery stock pt.2 and deciduous structure stream. There are the linden at the nursery (around 19 min) and a first work a little later in the second stream.
regards Bernd