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

[Johnnyd]

When I harvest air layers, I cut the stem well below the girdle, and I do not trim this 'stub' until the first repotting. I don't use any sealants.
IOW, the two layers I have now still have this 2 to 4 inch long 'stub' below the girdle. I simply remove the plastic that was covering the sphagnum and pot the works in a standard garden center plastic pot that I fill with Turface MVP. Usually this is 5 gallon size pot. I screw two diametrically opposed bamboo sticks to the pot and tie the upper parts of the layer to them so the roots won't be moved (analogous to what landscapers do when planting trees).

My one successful layer was the largest I had made until the two I currently have that were harvested Aug/Sep 2018. It was about 3 feet tall with a one inch-ish caliper. This year's layers are close to 4 feet and about 1.25 inch calipers.

My normal habit is to be repotting the layers about now, and trimming off the stub up to the bare wood in the girdle. I did not this with some of last year's layers, yet they crapped out too. I am not repotting and trimming this year's layers (meaning the two layers I potted last Aug/Sep versus last year's = harvested Aug/Sep 2017).


@River's Edge raised this possibility earlier so I did spend some time in the winter picking sphagnum away from the (adventitious) root collar - more so on one than the other. Correspondingly, I kept the MVP level lower with the 'picked' one.
Again, the wad of sphagnum is about fist size and it is set in the upper half of the depth of a 5 gallon plastic nursery pot filled with MVP. Roots grew out radially since last Aug/Sep to the extent that the pot of Turface is fully populated, on the surface anyway. For me, the problem hasn't appeared until after the first leaves are out - we're not quite to that time.


What are the details of what you do / you done, @Johnnyd?

I did not seal the stub on the bottom.
I did remove as much of the old sphagnum moss as possible. It was placed in boons mix with some fresh sphagnum on top. When is got warm in January/ February I did a root drench with the H2O2 solution you recommend. When buds swelled I alternated between daconel and Lyme sulfur every 2 weeks. Also been fertilizing plus "Root Ruckus ". I did not repot it this spring because I thought it was common practice to leave it alone until the following spring.

 

[0soyoung]

I did a root drench with the H2O2 solution

Thanks for mentioning this. I have as well, but just in the last month I administered a couple of peroxide drenches to both of my layers. Thx!!

 

[0soyoung]

I have an hypothesis that this is all due to air layering horizontal shindeshojo branches. I am not certain, but believe that my one success was, in fact, my sole layer of a vertical stem - an extra apex I eliminated from my landscape specimen.

As always before, the two layers I made (harvested and potted) in 2018 leafed out this spring (mid to late April as best I can recall), They were both looking good, and then all the foliage on both suddenly went weepy and withered, just about a week ago now. Again I noted necrosis (i.e., black-ish bark) near the soil level that I hadn't noticed a few weeks ago. Possibly because I went directly to an autopsy this time, I noted

1. Roots originated from one side of the branch - that was the underside of the branch
2. The bark necrosis was spreading from around the root origins - the opposite/upper side bark was still green
3. There were no white root tips --> consistent with dead roots

In 2018 I also made a small air layer on my one successful past layer, left it in place through the winter and just harvested and potted it a couple of days ago (i.e., I have a second shindeshojo air layer success!! ???). While it may refute my hypothesis, I do believe all is well with it and that it will live on.


It is normal for the adventitious roots of horizontal branches to appear just on one side, the underside of the branch because auxin levels are inherently higher on the underside of branches. I've observed this one-side rooting on several other species/cultivars that I've layered. It is just that with them, it didn't lead to fatality. So, 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.

I am now asking myself how I might demonstrate that I am onto something (as opposed to being lost in space)? The idea that I have is to layer another horizontal branch, but pot it horizontally instead of vertically as I've always done. Presumably it will survive through the following spring. Then in late summer, as if it was a freshly harvested air layer, repot it vertically (this would be Sep 2020). Per my hypothesis, it will die in the same fashion as all of my past failures in the following spring (spring 2021).

Two years for what amounts to a plausibility demonstration
I wish I could think of a quicker way.

 

[River's Edge]

I have an hypothesis that this is all due to air layering horizontal shindeshojo branches. I am not certain, but believe that my one success was, in fact, my sole layer of a vertical stem - an extra apex I eliminated from my landscape specimen.

As always before, the two layers I made (harvested and potted) in 2018 leafed out this spring (mid to late April as best I can recall), They were both looking good, and then all the foliage on both suddenly went weepy and withered, just about a week ago now. Again I noted necrosis (i.e., black-ish bark) near the soil level that I hadn't noticed a few weeks ago. Possibly because I went directly to an autopsy this time, I noted

1. Roots originated from one side of the branch - that was the underside of the branch
2. The bark necrosis was spreading from around the root origins - the opposite/upper side bark was still green
3. There were no white root tips --> consistent with dead roots

View attachment 243070 View attachment 243071

In 2018 I also made a small air layer on my one successful past layer, left it in place through the winter and just harvested and potted it a couple of days ago (i.e., I have a second shindeshojo air layer success!! ???). While it may refute my hypothesis, I do believe all is well with it and that it will live on.


It is normal for the adventitious roots of horizontal branches to appear just on one side, the underside of the branch because auxin levels are inherently higher on the underside of branches. I've observed this one-side rooting on several other species/cultivars that I've layered. It is just that with them, it didn't lead to fatality. So, 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.

I am now asking myself how I might demonstrate that I am onto something (as opposed to being lost in space)? The idea that I have is to layer another horizontal branch, but pot it horizontally instead of vertically as I've always done. Presumably it will survive through the following spring. Then in late summer, as if it was a freshly harvested air layer, repot it vertically (this would be Sep 2020). Per my hypothesis, it will die in the same fashion as all of my past failures in the following spring (spring 2021).

Two years for what amounts to a plausibility demonstration
I wish I could think of a quicker way.

Just to supplement your hypothesis i am inserting a picture taken in Japan. I have the habit of taking a lot of snaps showing techniques or different approaches. Later on i try to reason out why it was done that way. Positioning the pot differently may assist in keeping even moisture and air levels around the entire circumference.

 

[0soyoung]

In 2018 I also made a small air layer on my one successful past layer, left it in place through the winter and just harvested and potted it a couple of days ago (i.e., I have a second shindeshojo air layer success!! ???). While it may refute my hypothesis, I do believe all is well with it and that it will live on.

I did harvest this "layer from my one successful layer" this spring. It leafed out and then started slowly losing leaves and continued doing so all season long until about a week ago I noticed some new leaves . I take this to say that this layer succeeded, making it #2 out of tens of attempts. This was (also) a vertical stem.

I also just took note that whitish areas that are somewhat like the normal splotches of bark that show up on a.p. were actually areas where bark had popped off.

I've never noticed such before on any of my trees.

Does this represent bug damage? Does this represent the after effects of a pathogen? Whatever causes/caused it, doesn't provoke a damage reaction that clogs the xylem, hence it seems to be non-lethal and largely cosmetic.

... hmmm

 

[sorce]

I skipped page 2, my apologies.

I believe it's the sphagnum.

Same black death sphagnum always brought me. Well, I didn't keep doing it long, and stopped having the problem.

Is it still one success? Did it keep the sphag?

Sorce

 

[0soyoung]

@sorce, this one stayed "on the tree" overwinter, all the while (since the girdle was cut in spring 2018) in sphagnum. This is the only instance of 'spring harvesting' of an air layer. All other layers were harvested in late-summer/early-fall and potted over the winter; then repotted in spring.

I removed all the sphagnum this past spring just as I have with all shin de shojo layers I have ever attempted.

I believe the mother of this latest layer was a vertical stem from my landscape specimen. This latest (and my second successful shin de shojo air layer) was a vertical stem of this one successful layer. The multitude of failures I am certain were horizontal branches on the landscape tree.


I have never noticed this 'popped bark' phenomenon before on any tree of mine. Maybe I am guilty of just not paying attention.

 

[sorce]

have never noticed this 'popped bark' phenomenon be

Lol that's up there!

They didn't believe the pill bugs were eating my lemon.
The damage looked similar.

I can't believe horizontal or vertical would make a difference.

Is this the only one that was left to overwinter on the tree?

Something about sphagnum with soil, and is there a time length before soil is introduced, that allows the wound to heal before the soil introduces the pathogen, which the wet sphagnum accelerates growth of.....

I never had problems with sphagnum alone.
Only with soil too.

Sorce

 

[kouyou]

@0soyoung when you severed this most recent one, how was the volume of roots and were they 360 degrees all around the trunk?

for shin deshojo, i was told to perform the layer in spring, and sever in late summer/early fall the next year (18 months later). (i recently learned that seigen is done this way in japan for valuable tops of mature bonsai trees)

despite this advice, I just air layered one spring 2019, and severed it about a week ago. I placed it in the shade and kept it well watered. although it had a nice volume of roots, about 30-40% of the leaves dried up (they looked like the leaves in your bark-popping photo), while the remaining 60-70% of the leaves are in perfect condition! it is not as though some branches went dry and others were ok. rather, on the same branch i can have both dry leaves and perfect leaves!! when it started to happen I couldn't believe me eyes!

when i severed after only 5 months i had 360 degree roots, but there were gaps between each root. what i mean is, i had about 9-10 main roots emerging from the tree (which then ramified), but the space in between each of 9-10 roots on the circumference of the trunk was a bit much for my taste. I can't help but wonder whether a more substantial root mass --produced over 18 rather than 5 months-- might help this cultivar

 

[0soyoung]

They didn't believe the pill bugs were eating my lemon.
The damage looked similar.

✔

I can't believe horizontal or vertical would make a difference.

Is this the only one that was left to overwinter on the tree?

yes

I never had problems with sphagnum alone.
Only with soil too.

Only sphag and/or MVP.

 

[sorce]

MVP

I have a feeling of too water retentive in regards to this, rather, what I used as "turface".

yes

I believe in the thing about low branches being more susceptible to rooting. For BS reasons though really.

If anything the very nature of a airlayer in nature lol is horizontal yes?

I would eliminate this as a possibility for that reason alone.

I appreciate your scientifical approach a man to understand tree.
But I think it would behoove you to forget that and think as the tree would. Then when you resume scientifically thinking, the answer will be present.

Sorce

 

[sorce]

Wasn't the successful one also dominant, apical?

Sorce

 

[0soyoung]

@0soyoung when you severed this most recent one, how was the volume of roots and were they 360 degrees all around the trunk?

IIRC there were three groups of roots around the circumference, but I'm uncertain. What I do remember clearly is that the bag sort of slipped down, so the roots made a loop, like the rim of a bicycle wheel. I left it be when I potted it, sphagnum free, in MVP.

for shin deshojo, i was told to perform the layer in spring, and sever in late summer/early fall the next year (18 months later). (i recently learned that seigen is done this way in japan for valuable tops of mature bonsai trees)

I easily get an abundance of adventitious roots by roughly now, after having cut the girdle this past spring. Generating/growing roots has never been a problem. What other possible reason would there be for such a long time?

I just air layered one spring 2019, and severed it about a week ago. I placed it in the shade and kept it well watered. although it had a nice volume of roots, about 30-40% of the leaves dried up (they looked like the leaves in your bark-popping photo), while the remaining 60-70% of the leaves are in perfect condition! it is not as though some branches went dry and others were ok. rather, on the same branch i can have both dry leaves and perfect leaves!! when it started to happen I couldn't believe me eyes!

This is exactly as this one of mine. Curious, but after most of the season, voila new leaves! For a long time I thought this to be the same ole shin de shojo layer death in slow motion.

when i severed after only 5 months i had 360 degree roots, but there were gaps between each root. what i mean is, i had about 9-10 main roots emerging from the tree (which then ramified), but the space in between each of 9-10 roots on the circumference of the trunk was a bit much for my taste. I can't help but wonder whether a more substantial root mass --produced over 18 rather than 5 months-- might help this cultivar

I had similar issues with a number of my 'Orange Dream' air layers. They have tended to make more roots over the years. I've also noted that with roots on only one side, a flaring occurs at what was the top of the girdle. My thinking is that stuff comes down the tree in the phloem and cambium and runs into nowhere to go. So the phloem has become patterned in this flare to go around to the roots. So, were I to make two cuts to isolate a chunk of this ring, the escape route for auxin is cut off and this isolated segment ought to make roots. I think it works, but haven't confirmed it as yet. Maybe only patience is needed and not cuts.

 

[0soyoung]

Wasn't the successful one also dominant, apical?

Sorce

A stem that grew vertically, yes.

 

[0soyoung]

Referring to post #45:

I repotted it again 29 Feb 2020 (technically still winter, but it felt like spring) to see what I could see.



That 'ole necrosis' is clearly evident and it is apparent to me that the original layer roots all died because of it (a few black ones visibly remain).

I want to infer that this necrotic process was what caused it to weaken in the weeks after I harvested it. And that then, almost like a cutting, it re-rooted, making those healthy roots (light colored roots on the left) by last August.

 

[0soyoung]

Referring to post #43

I did harvest two (2) new horizontal branch layers in 2019. I simply removed the plastic wrapping, leaving the sphagnum and adventitious roots undisturbed when I potted them. They spent the fall and winter on a slight incline, approximating the angle at which they were on my landscape tree. I recently repotted both of them to remove the sphagnum. Roots on both are only on the underside, as expected. I found new spring root growth and no sign of 'the necrosis'. Both are now in the same places and inclinations as they spent the past fall and winter and are breaking bud.

Healthy roots on layer as depotted on 15 Mar (this would be the underside) ,

View of the top side of this layer (call it 'a') after combing out the rooting sphagnum.
Note the callus, girdle and blackened stub of the stem below - no black around or above the roots. I kept the stub so that I could drive a screw through the bottom of a black plastic pot into it to stabilize the roots from moving around in the pot of MVP.


Healthy roots on the second layer (layer 'b') as depotted with a little water jetting . Again, note the nice white tips indicate actively growing roots.

View of the topside of layer b after sphagnum removal .,
and a view showing the underside


Except for the sorta-horizontal storage, this is exactly as my past experiences. I'm still mulling over my next step(s).

 

[Woocash]

Referring to post #43

I did harvest two (2) new horizontal branch layers in 2019. I simply removed the plastic wrapping, leaving the sphagnum and adventitious roots undisturbed when I potted them. They spent the fall and winter on a slight incline, approximating the angle at which they were on my landscape tree. I recently repotted both of them to remove the sphagnum. Roots on both are only on the underside, as expected. I found new spring root growth and no sign of 'the necrosis'. Both are now in the same places and inclinations as they spent the past fall and winter and are breaking bud.

Healthy roots on layer as depotted on 15 Mar (this would be the underside) View attachment 292845,

View of the top side of this layer (call it 'a') after combing out the rooting sphagnum. View attachment 292846
Note the callus, girdle and blackened stub of the stem below - no black around or above the roots. I kept the stub so that I could drive a screw through the bottom of a black plastic pot into it to stabilize the roots from moving around in the pot of MVP.


Healthy roots on the second layer (layer 'b') as depotted with a little water jetting View attachment 292847. Again, note the nice white tips indicate actively growing roots.

View of the topside of layer b after sphagnum removal View attachment 292848.,
and a view showing the underside View attachment 292849


Except for the sorta-horizontal storage, this is exactly as my past experiences. I'm still mulling over my next step(s).

This thread is intriguing, but I bet it’s pretty frustrating. Would putting them in the ground for a year or two have any benefit potentially? As in, more of a natural type of over wintering and to establish some strength and vigour?

 

[ChrisChung]

Really interesting thread. Do you have anywhere I can read up more on the work you've done and the results they bore @Wires_Guy_wires ?

Sorry I don't have much to add to this thread, still a newbie.

 

[River's Edge]

Referring to post #43

I did harvest two (2) new horizontal branch layers in 2019. I simply removed the plastic wrapping, leaving the sphagnum and adventitious roots undisturbed when I potted them. They spent the fall and winter on a slight incline, approximating the angle at which they were on my landscape tree. I recently repotted both of them to remove the sphagnum. Roots on both are only on the underside, as expected. I found new spring root growth and no sign of 'the necrosis'. Both are now in the same places and inclinations as they spent the past fall and winter and are breaking bud.

Healthy roots on layer as depotted on 15 Mar (this would be the underside) View attachment 292845,

View of the top side of this layer (call it 'a') after combing out the rooting sphagnum. View attachment 292846
Note the callus, girdle and blackened stub of the stem below - no black around or above the roots. I kept the stub so that I could drive a screw through the bottom of a black plastic pot into it to stabilize the roots from moving around in the pot of MVP.


Healthy roots on the second layer (layer 'b') as depotted with a little water jetting View attachment 292847. Again, note the nice white tips indicate actively growing roots.

View of the topside of layer b after sphagnum removal View attachment 292848.,
and a view showing the underside View attachment 292849


Except for the sorta-horizontal storage, this is exactly as my past experiences. I'm still mulling over my next step(s).

Roots look great. Nice progress to this stage. I am wondering if a variation in the potting medium at this point would make a difference! Perhaps something with a bit less retentive capacity, then covered with shredded sphagnum to reduce evaporation, then water with addition of peroxide drench occasionally! Light dosage of fish fertilizer after bud break.
Trying to retain moisture without water in spaces! I would try straight pumice with 1/8" particle size worked carefully with chopstick between the roots.
The purpose being to reduce the risk of fungal issues and the effect of water freezing during colder temperatures next winter!
Just grasping at straws.
I am trying some of the same approaches with my Prunus cuttings and the results are encouraging. Not same species but combatting the same side effects of root development I believe.

 

[0soyoung]

After repotting the layer, last mentioned in post #55 (with 2 good roots), it is again not doing well. Leaf margins were starting to burn, so I moved it into deeper shade. I think this is just a symptom of 'not enough roots' to keep up because I affected a bit too much root damage in the repotting process. The margin burning looks 'conventional' and not like the bizzarre margins I've previously noted with 'the necrosis'. Of course, "we'll see".

The other two air-layers from 2019 are still laying horizontal, but in shade. So they are just now slowly leafing out. I've decided that they will stay this way until at least August 2020. I am thinking that, at that time, I will set one of them vertical to emulate what I've done with air-layers that I harvested in the past. But, if these two just survive until then, I think I will have pretty well demonstrated my hypothesized explanation for all these years of failure.