What's the Deal with A.P. 'Shin deshojo' Layers? Brainstorming Needed.

[River's Edge]

What about air layering a horizontal branch but laying the pot down to place the horizontal branch vertical to check your theory?
Pretend the wind blew it over and see if the roots distribute more evenly and the survival rate is higher.
Or wire the branch more vertical prior to air layer as one does positioning for eventual thread grafting on cultivars that lignify faster?
I think there are enough variables and approaches to keep this experiment going for a few more seasons.

 

[0soyoung]

These are sizable branches, one-inch-ish. They are branches that my wife and I decided we didn't want on our landscape specimen. I layered them instead of just lopping and tossing them. There is no possibility of 'wiring them up' before layering. For cuttings, yes

All (but one) of my layers over the years were horizontal branches. They were harvested in Aug/Sep and potted vertically. They trived going into winter. I repotted them before bud break the following spring to remove the sphagnum. They went back into pots vertically. Everything looked okay. They leafed out and collapsed. After a few seasons of this I began to notice the necrosis.

Now I've got, for the first time two horizontal layered branches that were treated like all in the past EXCEPT, I pretended they got blown over and have been laying horizontally since I harvested them in 2019.

There certainly are enough variables to make at least a master's degree thesis study with, but my objective is simply to understand why I, air-layer maniac, could have failed with shindeshojo so consistently over the years. Unless something really surprising happens, I will either adjust my thinking toward making something like rafts or semi-cascades or just toss them.

 

[Wires_Guy_wires]

It seems like they're not turgid enough to get sap to the upper parts.
This count hint towards the roots being to weak to induce a pushing pressure, or the foliage too weak to induce a drawing pressure.

Did you seal the trunk cuts in any way? It might be that case that their vascular system can't beat gravity.

This is all very weird and I'm willing to help in the brain storming.

 

[River's Edge]

These are sizable branches, one-inch-ish. They are branches that my wife and I decided we didn't want on our landscape specimen. I layered them instead of just lopping and tossing them. There is no possibility of 'wiring them up' before layering. For cuttings, yes

All (but one) of my layers over the years were horizontal branches. They were harvested in Aug/Sep and potted vertically. They trived going into winter. I repotted them before bud break the following spring to remove the sphagnum. They went back into pots vertically. Everything looked okay. They leafed out and collapsed. After a few seasons of this I began to notice the necrosis.

Now I've got, for the first time two horizontal layered branches that were treated like all in the past EXCEPT, I pretended they got blown over and have been laying horizontally since I harvested them in 2019.

There certainly are enough variables to make at least a master's degree thesis study with, but my objective is simply to understand why I, air-layer maniac, could have failed with shindeshojo so consistently over the years. Unless something really surprising happens, I will either adjust my thinking toward making something like rafts or semi-cascades or just toss them.

Is it possible because you are pushing the boundaries of juvenility ( if that is a word) by air layering such thick material that one of the issues might be the stub as it naturally decays after separation. One of the guidelines suggested for using sealant is pruning cuts of larger sizes. I believe in your posts you have indicated that you do not seal the stub.
One hypotheses may be that sealant could prevent or delay the decay and possible necrosis, allowing for stronger root formation which in turn could naturally defend against the effects of the decay long term.
Of course the other issue is the age of the material selected for air layering with more juvenile material having a much higher chance of success.
I understand that we often cut downward roots on maples leaving open scars in the root ball to heal on there own without sealant. These scars have the benefit of being in very close proximity to healthy feeder roots. Even though that is the case, one can use sealant on the larger cuts to delay or prevent decay. The stubs we leave after air layering ( for reasons of stability) can often decay quickly creating poor conditions for the transplanted air layer.
It may be wise to remove the stub, seal and secure the new air layer by other means.
Apical air layers tend to be more juvenile even if the same thickness as horizontal branches take longer to attain the same thickness.
Just throwing out other aspects for consideration.

 

[0soyoung]

Did you seal the trunk cuts in any way? It might be that case that their vascular system can't beat gravity.

I understand that we often cut downward roots on maples leaving open scars in the root ball to heal on there own without sealant. These scars have the benefit of being in very close proximity to healthy feeder roots. Even though that is the case, one can use sealant on the larger cuts to delay or prevent decay. The stubs we leave after air layering ( for reasons of stability) can often decay quickly creating poor conditions for the transplanted air layer.
It may be wise to remove the stub, seal and secure the new air layer by other means.

I have never sealed any air layer stub. If this is important, it is intriguing to think that covering exposed wood could erase the memory of which side of the branch was the underside (this is where the roots are and the area that becomes necrotic). Given the current circumstance, with two layers lying horizontal still with their stubs, I might remove the stub from one next spring (Feb 2021 -ish) and seal it with, say, Elmer's wood glue and then pot it vertically.

That is, assuming a layer without 'the necrosis' exists then. If so, I will have already demonstrated that keeping horizontal branches horizontal averts the necrosis issue. But it was done with stubs in place, which is far different from the wood exposure with the stub removed. Okay, I think I'll put that on the list, despite feeling that I'm being so open minded that my brain is about to fall out. But confirmation bias is a bad, bad thing IMHO.

Is it possible because you are pushing the boundaries of juvenility ( if that is a word)

I do think it is a word.

It might be true that all all the layers I've made have been lower (nearer the ground) on the tree. As I recall, though, a layer or two were at 2/3 to 3/4 the height of the tree. All failed in 'the necrotic way'. The one surviving layer was, I think, an extra apex. Just given these facts, I might conclude it is a juvenility thing. But I layered a slanting branch from this one successful layer and necrosis appeared after it was harvested and potted (vertically in late May 2019). This, I think contradicts the idea that juvenility is a primary factor.

It seems like they're not turgid enough to get sap to the upper parts.

That's pretty much what it is, in effect. Air layer roots connect directly to that season's new wood. Death of the cambium over this layer provokes a CODIT reaction that clogs the xylem so water cannot be transported.

We know that there is more auxin in the polar auxin transport stream on the underside of a horizontal branch, hence adventitious roots tend to form on the underside.

We also know that when we prune a branch we stop the auxin flow from above. It can be sustained for a time by the upward flow of auxin laden phloem sap, but eventually the auxin level drops below some critical threshold and the cambium dies affecting CODIT sealing of the cut end.

So my hypothesis is that erecting and air layer of a previously horizontal branch reduces the auxin level in the PAT flow below this critical threshold --> cambium death (seen as blackish bark/necrosis) in the area of the adventitious roots.

There is an additional wrinkle, though. That is, this necrosis seems to be a spring thing, not happening in summer or fall. I don't understand this, but I do take it as a fact of this problem. Historically layers were potted vertically with the wad of sphagnum intact/insitu. They thrived through the end of the season. The following spring I combed out the sphagnum and removed the stub. No necrosis was noted. Subsequently they would start leafing out and would then suddenly collapse shortly after expressing first leaves. In the last few years of this history I noted the necrosis. I think it was there in the earlier years, but I overlooked it, as I remember being mystified by all the healthy roots and, in my naivete, didn't 'dig deeper',

So what goes on with the phytohormones that might explain why this is a spring thing? Any ideas?

 

[River's Edge]

So my hypothesis is that erecting and air layer of a previously horizontal branch reduces the auxin level in the PAT flow below this critical threshold --> cambium death (seen as blackish bark/necrosis) in the area of the adventitious roots.

And yet we wire down branches so the branch tip is lower to promote more exposure , increase lateral growth and less auxin control? A very effective additional component to improve interior foliage in conifers. So it would seem that going vertical would have the opposite effect of increasing auxin flow. Assuming the plant has not been pruned to reduce auxin flow.
I am not familiar with the coding response, so this may be a very separate issue.

 

[0soyoung]

And yet we wire down branches so the branch tip is lower to promote more exposure , increase lateral growth and less auxin control?

But the underside of the branch is the still the underside - it had and will continue to have a higher level of auxin in the PAT stream than the top. This is fundamentally how gravitropism works. Auxin on the underside causes more cell elongation (in the newly created wood) on the underside than the top, making a stem tend to curve up. I know you've seen this innumerable times in the forest. It is very common in the mountains with winter snow pack and even in the local forests here. Young tree knocked over, apex turned up, and now one sees a nice up sweep to a vertical trunk waayy uuuup there (gawd, I could use a gazing up emoticon right now ).

 

[Wires_Guy_wires]

I'm thinking out loud here, maybe it could lead to some more brainstorming: It would be nice to see if you can take a cutting and note how it collapses, in the sense of what tissue dies first. This would provide a more specific zoom in on what's happening, but on a smaller scale. This could be a good check if it's the gravity, or the nature of the tissue; gravity affects tiny cuttings less than it would affect an air layer. They would succumb in a different manner, or not at all if it's a gravity/turgor/PAT issue. (By the way, the studies showing that roots produce auxins locally are slowly being published, there's growing evidence that PAT is real, but that there's also a local system on the side).

If it's good at compartmentalizing decay (CODIT), then I'd suspect the parts with foliage and roots (probably the first node or two) to survive longer than the rest because there's a root-foliage feedback system. From what I'm reading, the air layer dies as a whole after leafing out. This can mean two things: the compartmentalization is happening above the newly built root system, everything gets shut off, OR there is no compartmentalization happening (could be because death happens too fast, or for other reasons).

I think bleeding could still be an issue, it would show blackish, orange, yellow or brown goo in the moss close to the cut site when you dig them up. Like the wet stuff that comes out of spoiled fruit. Then again, the moss would soak it up.. Would be hard to check. You'd have to make tea out of the removed sphagnum and check its color.

There's an entire topic about hardening off in my tissue culture book. This might will be a long shot, but what if this is the case: you separate them after they've been building resources over the course of summer, they thrive for a while, depleting those resources, tricking you into thinking they're OK on their own roots. Then they go dormant. Spring happens, you do your thing with the repot, they leaf out, they deplete their resources before they can build new ones and they collapse. A long shot, but removing the moss and replacing it with bonsai soil while they're still on the parent tree, let them leaf out (with parental resources) and then separate them might just do the trick. Unconventional and unpractical, but it would leave them with a surplus of resources to jumpstart them being on their own roots.

I've had wood lice chewing off the roots and introducing infections. Same goes with those tiny glasslike worms. The worms turn tissue to mush, the wood lice gnaw off chunks like in that lemon tree thread of sorce (tiny beavers or something?). But I think you would've mentioned that.

How do the roots look when you repot? Do you have those fat ropes with little adventitious roots, or more of a fine mat of roots? I know some maples make different roots in high moisture media, those wouldn't work well in bonsai soil and would need time transitioning to finer feeders. If that transition starts happening after they've leafed out.. They could collapse as well. In a matter of days after leafing out. This would however let the apex die first, and slowly go down the tree. I'd suspect the bottom part to live the longest.

This all doesn't make any sense!

 

[Canada Bonsai]

my objective is simply to understand why I, air-layer maniac, could have failed with shindeshojo so consistently over the years

i can't help but ask, are you absolutely sure that your shindeshojo is 'real'. If so, could it just be a 'bad' specimen or 'strain'?

I am asking because I now have 3 'strains' of shindeshojo in my yard (and at least 4 Deshojo 'strains'): one strain was imported from Japan 35 years ago, and the others came from the west coast USA (from separate growers, who each or either may have obtained their specimens from japan, i don't know). Each 'strain' behaves very differently even under the same conditions when it comes to air layering and cuttings. My strain from japan produces cuttings that are as vigorous as my kashima and arakawa cuttings, and air layers as vigorous as my shishigashira. The others 'strains' are less vigorous/viable. Meriggioli also produces (shin)deshojo air layers no problemo! (he is, i imagine, working with material from Japan)

But the important thing is that air layering deshojo and shin deshojo should be easy, and you're an expert at it! The problem has to be the tree itself, not the techniques or procedure. Are you only working with 1 mother plant?

 

[0soyoung]

Gawd, this is priceless!

 

[0soyoung]

are you absolutely sure that your shindeshojo is 'real'. If so, could it just be a 'bad' specimen or 'strain'?

I am not. It was identified as shindeshojo at a large garden center nursery north of Seattle when I bought it. As its leaves age, they shift to dotted green and seem almost translucent - similar to ukigumo, but as though the leaf is thinner. Amazingly, I cannot dredge up any photos! It does seem a bit 'different' in this respect.

But this is irrelevant to me. Long ago I knew it was the tree's fault and not mine! I just like finding things out. Maybe it is just my one tree (now more than a decade as our landscape specimen) is a one of a kind. But it is my tree and it has done this repeatedly. I want to know why. Simple terms, not to the depth of a scholarly paper. "Its just your mother tree" is not a satisfactory answer. That's all.

How do the roots look when you repot? Do you have those fat ropes with little adventitious roots, or more of a fine mat of roots?

I've always used plastic wrapped damp sphagnum for these shindeshojo layers. I've always gotten abundant adventitious roots on the layers. I think my tree is quite 'easy' in this respect. The roots, of course, are the characteristic fragile white fleshy things. I simply remove the plastic cover and pot the works in Turface MVP in Aug/Sep which gives it until November-ish to grow. I have fibrous roots by the following spring (see the pix in post#56 for example).

Still a lot to chew on. More to follow, ...

 

[0soyoung]

Found IT! I mean a pic of my shindeshojo's leaves. First thing in spring they are all that delicious coral red with yellow mid-veins.
All three stages in one pic.

 

[Canada Bonsai]

As its leaves age, they shift to dotted green and seem almost translucent - similar to ukigumo

That is very very odd!

Here is a picture from Meriggioli's book. I'm sure you already know, your white speckling and light green coloration are unusual -- looks like you're missing the brown/purplish stage when the red starts to fade and the dark green starts to come through!

 

[0soyoung]

So my tree is a kumo deshojo and not a shin deshojo

It seems to be unusual for Japanese maples that are not prostrate growers to have horizontal branches. Most of the varieties we favor for bonsai naturally grow upright, vase-shaped profile, loosely speaking.

Back in my noob/air-layering-maniac days I tried to air layer my acer japonicum 'Green Cascade' and had similar trouble (got lots of adventitious roots, thrived going to leaf drop, and collapsed shortly after leafing out in the following spring). It is a fabulous landscape tree, but the leaves are monstrously large for bonsai purposes, so I really didn't care (then) and just moved on. I also have three a..p. red dissectum that were in the landscape when we bought my present home. These are, in my estimation, prostrate. I have not been interested in layering one of these, but red dissectums have a reputation for either not being air-layer-able or too weak on their own roots (IOW, sane people don't bother or just quickly move on).

The point I'm trying to make is that my shindeshojo problem may, in fact, not be unusual. It might be the reason we don't air layer prostrate growing maples. But so ...?


Okay, now: Everybody with an a.p. 'Kiyohime', air layer one of your branches and pot the harvested layer upright. Report back about this time next year!!!

 

[0soyoung]

Ref. post #60

All the foliage has flagged on the layer of the one good layer I have (the one that had 2 good roots), and it is reasonably clear that the necrosis has completely girdled the trunk this time, though it is obscured on the topside side by the natural tan bark.
On what was the underside of this layer, it easy to see that the necrosis has progressed up both branches (the tan stick in the background is a bamboo pole).



Meanwhile, the two 2019 horizontal branch layers from my landscape tree both have hardened foliage. Both remain in a horizontal position, approximating their original attitude on the mother tree.

 

[0soyoung]

This is about as solidly green as my shin deshojo leaves ever get (these are leaves of my sole surviving air layer)



These green leaves will become speckled (like those in the prior pic) in summer.

 

[namnhi]

Ref. post #60

All the foliage has flagged View attachment 300397 on the layer of the one good layer I have (the one that had 2 good roots), and it is reasonably clear that the necrosis has completely girdled the trunk this time, though it is obscured on the topside side by the natural tan bark. View attachment 300403
On what was the underside of this layer, it easy to see that the necrosis has progressed up both branches (the tan stick in the background is a bamboo pole).

View attachment 300396

Meanwhile, the two 2019 horizontal branch layers from my landscape tree both have hardened foliage. Both remain in a horizontal position, approximating their original attitude on the mother tree.

Your problem is turface and osmocot fert! LOL

 

[PiñonJ]

with shindeshojo, I am suggesting that the cambium on the underside of the branch is programmed for higher auxin levels and that the low levels of spring are sufficient to trigger the damage response apoptosis of the cambium. This cuts off the supply of auxin to the roots and, of course, they die and so goes the tree.

@0soyoung, do you have any experience with Sango Kaku? I re-potted one this spring and it was doing fantastically. I was going to trunk chop it, but I decided why not air-layer the top? I did so on 27 April and it seemed perfectly happy until mid-June, when I started noticing bark discoloration similar to what you've shown. It took maybe a week for it to spread all the way around the trunk and the leaves finally wilted. There's no discoloration above the layer, but I assume there are now no growing roots to keep it hydrated and inspecting the layer revealed very few roots, as of last week. I was wondering if you think these trees are so hormonally sensitive that the cambium underwent apoptosis. Is it affected by the amount of transpirational demand on the roots vs. how much auxin is being received from the canopy? In other words, would it have been more likely to survive a trunk chop, rather than trying to layer it? Here are photos from 6/17 and 6/20 (as usual, when I decrease the image size, it rotates 90 degrees):

 

[0soyoung]

@PiñonJ, I haven't a Sango Kaku, but as far as auxin flow is concerned, there is no difference between girdling and pruning/chopping. In other words, if this necrosis was caused by the girdle you made, chopping would have produced the same outcome.

In my experiences, roots of most species have starch reserves adequate to live on for 12 to 18 months, so I would bet that you would have found live roots had you de-potted the tree as soon as the tree 'flamed out'. The cambium apoptosis triggers the compartmentalization damage response = clog/seal-up the xylem = there is a plug in the wood behind and somewhat above that point which stops the flow of water up the tree. Of course, this could be the end result of something killing the roots. I would imagine that a dose of copper sulfate as a root drench could do this, for example. I have my doubts that this is an intrinsic problem with SK, but no first-hand knowledge.

If you're infected with the 'just gotta know' bug, my thoughts are try again with more grafted SK about this size (possibly from different growers) and see if you get the same outcome. Another is to get a bigger SK and layer a branch or two that are a minor part of the canopy (no risk of dramatic reduction in auxin flow to the graft union). Then you get some SK on their own roots for bonsai and still have a big tree that you can then decide to chop/layer or just plant (or leave) planted in your garden/landscape.

 

[Owen Reich]

T

I’m looking for help to figure out why my a.p. Shin deshojo is so difficult to propagate by air layering.


Over the last 7 years or so, I’ve attempted something like 20, give or take, air layers of my a.p. Shin deshojo landscape specimen. Except for a couple of occasions that the girdle was bridged, I’ve always gotten harvestable layers in one season. I’ve always left the sphagnum in place and potted the layer in Turface with the stem secured to a bamboo support pole or two screwed to the wall of the pot so that there would be no movement to damage the roots. The layers have always thrived through the end of the season. The following spring they leaf out and then, around the point of hardening. collapse, regardless of whether left in situ or repotted ‘as buds swell’.


That is, except for one from three years ago (layered/harvested in 2015) that is still going strong and another from the year before last (layered/harvested in 2016) that made it through this past winter and is limping along now after nearly dying last season.


Just yesterday I did a little autopsy of two 2017 layers that just died. This year I’ve noted necrosis (i.e., ‘black’ bark) of the trunk (which just appeared in the last week), just above the root collar or soil line - the bark is still green above. You should see this necrosis in the following pix. The first pair of pix are of the root ‘ball’ popped from the pot and the necrosis on one of the two. The other pair are of the root 'ball' after washing and combing the roots of the other 2017 layer. In both instances I found a (very) few white, growing root tips.

View attachment 190638View attachment 190639View attachment 190640View attachment 190641

• Lots of roots.
• Thrives.
• Then dies the following spring
  • necrosis at the base of the trunk.

I need ideas of why this is happening.

They are likely getting a fungal infection in winter, or they may not have enough energy reserves stored for spring push (that’s just a guess). Suggest using long fiber sphagnum with a medium size Akadama sphagnum mix around layer site. Once you know you have roots filling layer container, removed container and add another layer of sphagnum. This will prompt a 2nd gen of roots and first gen will lignify before winter and detachment. That came from Bill Valavanis, and it’s worked every time I’ve done it.

The Japanese maple below was layered in this fashion 2 years ago. Had to cut 75% of roots off to get it into a pot. We used Hormodin 3 @ wound site for uniform radial roots.