First ever collected tree - Betula Pendula

[Per PF]

So it was finally time for my first dig (buds swelling+elongating). I had scouted this Betula months ago for its taper-potential, health and growing location (a local quarry, rock underneath and a flat loose-root-bed). Unfortunately I forgot to take photos of the process in the exitement..
It had lots of feeder roots and I kept a good chunk of original soil around them (about 4 cm thick). The roots were very one-sided, as it was growing on a slope facing south, and had basically just one big anchoring root towards its back and the rest towards the sun and down hill.

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It's planted in pumice+lava (50/50) with a good amount of sphagnum directly underneath the roots. I sealed the branches I had to cut with petroleum jelly (Vaseline).

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It's almost 25 cm around the base and it's 21 cm up to the divide were the thinner one is 13 cm around.
My future plans are to sloooowly reduce it down to a fairly straight (informal upright) tree of about 45 cm. For now I'm leaving it alone until at least next years growing season. I have read up on its branch-dropping-die-back-fondness.

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Thoughts and comments are always welcome Especially if you have experience in Betula reducing!

[Raging Bull]

Hi Per, that tree should do well for you there. I'm in South East Queensland and I don't think that kind of birch tree would do very well here. I have a tropical birch (Betula Nigra) that I've had for about a year now and it's thriving. It was bought as a garden tree from a local nursery and I put it into a larger pot to grow as a bonsai. I've pruned it a couple of times to start shaping it and have had no problems with it.
Cheers, Frank.

[Matt S]

Great post Per, lots of details on what you did. I have exactly zero experience in Betula other than the straggly specimens we have at work (I work for a Swedish company) which struggle through our summers, but I look forward to seeing what you do with yours.

Has anyone in Sweden tried to bonsai a Lingonberry tree? The small red fruits would look amazing!

Matt.

[shibui]

Birch are quite easy to transplant. You don't even need a lot of roots and they will survive and grow happily.
They do like lots of moisture so hopefully the sphagnum and old soil around the roots will be OK. Personally I do't like to put soil into pots because it causes too many problems with the roots.
Birch die back seems to e linked to shortage of water in summer or pruning in winter. I saw someone post that the secret is to prune in summer instead of winter.
I think leaving this one alone for a year to get started again is a good plan. See how it responds before making further plans for any pruning or styling.

[Per PF]

Thanks for the encouragement guys, I'll keep you posted on updates.

@Raging Bull I hadn't heard about Betula Nigra before, that's really cool (no pun int...) that there is a tropical variety! My main focus is trees I saw growing up in the northern parts of Sweden (above the Arctic Circle) - so I see why this species wouldn't do so well down there

@Matt S Thanks I try to document well so I'll hopefully learn from my mistakes along the way Unfortunately I don't think Lingonberries (very small shrubs) would be good bonsai candidates as they have very little wood-like tissue and not much taper (+I've heard they're difficult to cultivate in general). But transplanted together with the original moss they're growing in would make pretty cool kusamono - I'll keep that in mind!

@shibui I considered removing more of the old soil and I'm hoping I only reduced the stress to the tree and not set it up for root-rot, but fingers crossed... I'm adhering to Mauro Stemberger's advice about not over watering a collected tree and to gradually remove the old soil through repottings.
Thanks for the tip, I will wait at least until next years growing season to prune anything.

[Per PF]

The birch leafed out as expected and seems to be doing okay.

Some of the leaves have recently turned yellow due to lack of sun (it is the ones not in direct light all day). It is now summer here in Sweden btw.

The general question: A recently collected tree should be protected from the elements (?) BUT how do you handle a species such as Betula Pendula which at the same time needs a lot of sun?

In my specific case I think I will leave it as is until next spring when I move it to full sun/more wind. Because, it is the best position (I can think of) in the garden for protection and I'm going to heavily reduce this tree over the years, so some die back is not a problem.

What do you guys think?

[Per PF]

Regarding the full sun info I refer to Harry Harrington in the UK - lots of experience and similar climate: http://www.bonsai4me.com/SpeciesGuide/Betula.html

[shibui]

I think there is a balance needed between plenty of light and dehydration of the tree. I doubt that there is one rigid answer to this dilemma. Different species will require different conditions. The best location may also be different according to how many roots were retained at collection. The fewer roots your tree has the more protection it will need in order to grow enough new roots to sustain itself. It will probably also depend on timing. Early collected trees have a better window of mild weather to regrow roots while a later collection may need some assistance when warm weather comes.

I think we are inclined to think in terms of rigid rules but life is far more flexible than that. It is most likely that there is a wide window of possible conditions. It is also likely that this might explain the wide range of differing opinions on what is best. The fact that a tree has survived under one set of conditions does not necessarily mean that those are the best or only conditions.

I transplant many trees. Most are transplants from the grow beds and may not be indicative of all other collected trees but most of those trees go straight onto the nursery benches in full sun and I get close to 100% survival and very good growth from maples, elms, pines and junipers under those conditions. Many of the trees I collect from wild locations and other gardens end up on the ground under the nursery benches (mostly due to lack of space on the benches in the sun) where they get plenty of water but some shade. They also tend to survive very well.

A few yellowing leaves is not always a sign of imminent death. I agree with your decision to leave our birch where it is. Moving a tree to new conditions, especially more sun seems to cause more trauma and problems that we imagine.

[Per PF]

Thank you very much for your nuanced and thoughtful answer! Learning a lot

[Per PF]

Autumn update (autumn here in Sweden zone 7):

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The collected birch named Moby seems to be doing fine atm. It had a second flush of growth late summer, with significantly larger leaves

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It's been attacked by a horde of caterpillar larvae, fortunately I caught it fairly early (but they are fast!):

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I also had an issue with some sort of borer (reoccuring sawdust at the base). I tried to kill it with some wire, smother it with vaseline and finally got it with some trusty WD-40

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Although it probably doesn't need it I will still mulch the tree when we start getting frost. Come spring I'll place it in a full sun position and before bud break reduce it another 30 to 40 cm on both sides.

I noticed that the substrate has sunken down/depressed some over time and I'm guessing/hoping this is the original soil falling away. Anyone with similar experience?

[Per PF]

As we are at the almost start of spring here (it snowed today..) I decided to reduce my birch before things start happening:

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When I collected it I used petroleum jelly (Vaseline) to seal the trunk chops and they both got fungus/mold underneath this autumn, so in the name of science I put a commercial sealant on one and left the other as is. We'll see how that goes.

[Per PF]

Update early summer:
After winter storage and last years shady position most of the lower branches were dead but it's coming back now!
I'm giving it plenty of water and liquid fert. once a week.

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I'm planning on keeping the same sunny position over next winter (but slightly protected) to maximize sun.

[Per PF]

A belated update on my Birch, first Yamadori ever:

Following good 2021 summer growth.

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I repotted in spring last year 2022.
Swelling buds:

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Nice mycorrhiza and plenty of roots.

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Chopped back the bigger ones to fit into a plastic mica pot.

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Following good growth this year I chopped/reduced in midsummer

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I didn't want to wait another season to reduce since the tree was at maximum imbalance between pot size and foliage.
(So far no dieback...)

[Trimmy]

I’ve read that birch trees struggle with wound healing. What does this mean for long term styling of them? I have a small birch that I haven’t done anything to so far. Will clip and grow work or do I have to let it thicken and then cut it back?

[Per PF]

They have a propensity to drop branches or even trunks and instead shoot from the base. So the general advice I'm (not really )following is to avoid big cuts (material that needs trunk chopping), prune when the tree is active and has lots of energy and always keep a few/lot of spare branches (don't make your design dependent on one particular branch + ignore bar-branching). +They are very thirsty - at least over here in Sweden. Good luck!

Harry Harrington has some excellent info on his site:
https://bonsai4me.com/speciesguides/bet ... ch-bonsai/