oak bare root

[GavinG]

I have just lucked onto a graceful 1 metre oak tree, dug with its own garden soil. I want to bare root it, possibly putting it into pure pumice for safety. Has anyone any ideas? Safe or not?

Gavin

[shibui]

I believe some oaks don't particularly like severe root pruning but bare root does not seem to worry them. I've transplanted many English oak from seedlings to 2m tall - all bare root and no problems with those. Most also had the roots severely pruned at collection and grew well after.
Cork oak has been the one that sulks after root pruning here.

[melbrackstone]

Have you grown trees in straight pumice before Gavin? I only ask because the other day I went to root prune a Chinese Elm that was in a plastic pot that I'd half filled with pumice, and topped up with my normal bonsai mix. The roots of the Elm had basically stopped at the pumice, and looked like they'd all been burnt...all the big roots stopped at that level, and died off on the ends. None of the fine roots went into the pumice either.

I might have a dud lot, of course, but I have also lost another tree last year that was placed into pure pumice... I was slow to take it out, so the roots were all dead from top to bottom in that case.

[GavinG]

Thanks Neal, about 50% of the roots removed, and into pumice. Fingers crossed.

Mel, pure pumice has been my go-to for sick or vulnerable trees for a while - I bare-root old maples and plums and put them in pumice every five years or so to avoid root rot. They all seem to thrive in it, and the root system comes out dense and fibrous. It's interesting, they don't seem to need more water (but they are in larger pots than usual). Would your problems come from the climate - would the roots "bake" in the hot rocks in summer up there?

I'm curious what the problem is.

Gavin

[melbrackstone]

Mel, pure pumice has been my go-to for sick or vulnerable trees for a while - I bare-root old maples and plums and put them in pumice every five years or so to avoid root rot. They all seem to thrive in it, and the root system comes out dense and fibrous. It's interesting, they don't seem to need more water (but they are in larger pots than usual). Would your problems come from the climate - would the roots "bake" in the hot rocks in summer up there?

I'm curious what the problem is.

I understand a lot of people use pumice as a good way to pick up some older yamadori, and was keen to give it a go. I'm just wondering if mine had been harvested locally, and was still salty. I really don't know why this Chinese Elm stopped at the change in mix. I will give it a go after soaking it for a few weeks, perhaps. Will be still repotting for awhile, so I'll check and see if I have any similar problems with the plastic potted trees I did at the same time as the CE.

Thanks.

[GavinG]

I've seen problems with a sudden change of mix in other circumstances - a free-draining mix around a fine-grained Chinese-style mix is one example. It's something I try to avoid.

Gavin

[Stu]

I have read that the Japanese use pumice frequently to nurture stressed trees. As Gavin has suggested, it may be the change of mix. Many suggest a drainage layer in an ordinary pot is not good because the water is retained at the bottom of the soil mix where it meets the drainage.

[melbrackstone]

I've seen problems with a sudden change of mix in other circumstances - a free-draining mix around a fine-grained Chinese-style mix is one example. It's something I try to avoid.

Thanks Gavin and Stu. Yes I'm not doing that anymore...

[Luke308]

Have you grown trees in straight pumice before Gavin? I only ask because the other day I went to root prune a Chinese Elm that was in a plastic pot that I'd half filled with pumice, and topped up with my normal bonsai mix. The roots of the Elm had basically stopped at the pumice, and looked like they'd all been burnt...all the big roots stopped at that level, and died off on the ends. None of the fine roots went into the pumice either.

I might have a dud lot, of course, but I have also lost another tree last year that was placed into pure pumice... I was slow to take it out, so the roots were all dead from top to bottom in that case.

I grow my pines in 100% pumice and they love it. Deciduous may be a different story though.