The science of air-layering

So if a tree has no terminal bud the lack of auxin will not allow for a cutting or air layer to strike?

So, I'm left with little choice but to air-layer a trunk on a crab apple (in a pot) with a lot of trauma at the base.

Is a successful air-layer something you can count on?

If one were to do a thousand layers correctly, what is the rate of success? Is there a chaos factor involved where they just simply fail sometimes?

I am having 100% success on my air layers for the last two or three years. I've only layered vertical trunks and branches, and I've used the pot method. Crabapple is easy. If you do it right, it is almost certain to succeed.

michaelj said:

I am having 100% success on my air layers for the last two or three years. I've only layered vertical trunks and branches, and I've used the pot method. Crabapple is easy. If you do it right, it is almost certain to succeed.

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Good to know.

barrosinc said:

So if a tree has no terminal bud the lack of auxin will not allow for a cutting or air layer to strike?

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???

From one branch can I cut it in half and get two cuttings or does a cutting have to have a terminal bud?

barrosinc said:

???

From one branch can I cut it in half and get two cuttings or does a cutting have to have a terminal bud?

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Yes you can cut it in half to make 2 cuttings.
As long as there are leaves on both halves.

Air-layer locations on a tree and special considerations:

A: Tree has foliage above air-layer and below air-layer. No special considerations. "Safe" air-layer that will not stress the tree too much if it fails.

B: Considered a "ground layer" this is an air-layer at any level that is below the first foliage mass. You need to be careful when attempting this type of layer because you are severing ALL flow of carbs from foliage to the roots. Because they are being starved of carbs (food), the roots of the source tree will eventually weaken and die. You are in a race against time for the air-layer to develop roots and be separated, and/or the source tree to pop new buds below the air-layer. This type of layer runs the risk of killing the source tree roots (which may not be an issue if your plan was to discard the old roots anyway).

C: A successful way to execute two air-layers on one branch. Note that each air-layer has an uninterrupted pathway to its own mass of foliage to supply auxin.

D: A less successful way to execute two air-layers on one branch. Note that the lower air-layer does not have any foliage above it to supply it with auxin. If it generates roots, it will do so based on auxin that is already present in the phloem between the two air-layers. This may work on easy-to-root species (like a willow, for example) but should not be attempted on difficult to root species (for example most conifers).

Bonsai Nut said:

I started to think about stickying threads that are very specifically related to the kinds of questions we see over and over on the site and have really good guides or "how-tos". Air-layering, grafting, propagation, etc. I might move some to our resource area after they have been discussed for a while.

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I think it's a great idea! Also adding a bonsai "calendar" with times of the year to perform certain work, like repotting, pruning, wiring, etc. I know the tricky part is how to explain this based on weather which varies so much from location to location.

herzausstahl said:

I think it's a great idea! Also adding a bonsai "calendar" with times of the year to perform certain work, like repotting, pruning, wiring, etc. I know the tricky part is how to explain this based on weather which varies so much from location to location.

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A single calendar just won't work, while majority of BNut are based in North America, we do have members from all over the world. From New Zealand to Alaska, EU, Russia, Australia and Indonesia. No one calendar would be possible.

Also, there are many species specific adjustments that have to be made. Not all species want to be repotted in ''Spring''. Chaenomeles (flowering quince) and Diospyros (Persimmon genus) prefer a late summer repotting. Flowering quince will usually survive a spring repot, but often does better with late summer. Persimmons will die about 50% of the time if repotted in spring. They really need to be repotted later in the year.

Every species has its own ideal time. Larch want very early spring, Oaks and Cryptomeria are better repotted late Spring, about 2-3 weeks before the summer solstice.

When the air layering is complete and is removed do you then pot it in your normal bonsai soil?

Gary McCarthy said:

When the air layering is complete and is removed do you then pot it in your normal bonsai soil?

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Yes.

But roots grown in sphagnum are fragile. I put these in a plastic pot and stabilized so that the roots won't get moved around. Usually I screw a couple of sticks to the pot, opposite one another, and loosely bind the tree to them with some junk wire analogous to the common practice with landscape trees. Sometimes I drive a screw through the bottom of the pot and into the stub at the base of the layer. Regardless, the following spring I remove the sphagnum when I repot (possibly into a bonsai container). If you are layering a portion of a vertical stem (e.g., a trunk), you an fit a pot around it and grow your layer roots directly into your favorite substrate, thereby avoiding this added step to harden the new roots.

0soyoung said:

Yes.

But roots grown in sphagnum are fragile. I put these in a plastic pot and stabilized so that the roots won't get moved around.

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Just to be clear you put the layer with sphagnum still attach in the center of the pot then surround with bonsai soil?

coltranem said:

Just to be clear you put the layer with sphagnum still attach in the center of the pot then surround with bonsai soil?

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yes

great thread.

coltranem said:

Just to be clear you put the layer with sphagnum still attach in the center of the pot then surround with bonsai soil?

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I dont...wont....ever....

Sphagnum in pots rots roots for me in winter with no question.

Best to start with DE or Pumice, or perlite to begin with.

Then you ain't gotta worry.

I would say sphagnum has no place in my yard at all....
But I did find green Moss growing on some of my 50/50 top dressing recently...
But.......I may have a safer media to do this with than sphagnum too so......

@coltranem ....your biggest take-away...
Your yard is your yard.
Your climate is yours.
Your over wintering is yours.

Ask the right questions.

If 0so winters in a temp controlled greenhouse....
And you do not....

That's a giant difference.
Let alone your location.

Sorce

sorce said:

I would say sphagnum has no place in my yard at all....
But I did find green Moss growing on some of my 50/50 top dressing recently...
But.......I may have a safer media to do this with than sphagnum too so......

Sorce

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You don't have to worry about sphagnum in your top dressing. Once the living moss is established, the sphagnum disappears.

sorce said:

Sphagnum in pots rots roots for me in winter with no question.

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So much of bonsai is situational - depending on where you live, your micro-environment in your yard, etc. Of the members in our bonsai study group, we all do the same things, but we tend to do them a little differently.

This summer I attempted 8 air-layers. 4 I used my "preferred" old skool method of just wrapping the girdle in spaghnum moss. 2 I tried rooter pots and 2 I tried bonsai soil in a container. The 4 sphagnum moss ones all issued roots immediately, the other four all calloused over and I had to re-trim them and replace with sphagnum. It was a handful of data points and not statistically significant, but it still caused me to consider sphagnum as my "favorite" air-layer medium. It doesn't mean you can't work with other methods - it is just what has worked for me best in my limited experience in my yard

Sphagnum moss in soil for me lasts a year to a year and a half (similar to rough cut peat). I don't have root rot problems, but then again my climate (even in the rainy season) is still relatively warm and dry.

Hi All,
I have read through this amazing thread ( wondered if it was in the resources section) and have a question. I think someone else asked it also, with conflicting answers.
Using Bonsainut (admin) picture from above he marks a section D. I note that where there is NO leaves between air-layers the technique at lower layer will likely fail.
BUT, If there were leaves between both portions of section D, and you were desperate for many trees ( oops me kind of) then WOULD BOTH PORTIONS OF 'D' send roots? As there is an interrupted flow of food. Eg. Stops at first girdle.
Hope I explained myself?
Charles.

KiwiPlantGuy said:

Hi All,
I have read through this amazing thread ( wondered if it was in the resources section) and have a question. I think someone else asked it also, with conflicting answers.
Using Bonsainut (admin) picture from above he marks a section D. I note that where there is NO leaves between air-layers the technique at lower layer will likely fail.
BUT, If there were leaves between both portions of section D, and you were desperate for many trees ( oops me kind of) then WOULD BOTH PORTIONS OF 'D' send roots? As there is an interrupted flow of food. Eg. Stops at first girdle.
Hope I explained myself?
Charles.

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If I'm understanding you correctly. If you put leaves between the two layers of section D you are turning it into section C. The only difference I can possibly come up with is the amount of leaves in between the two points. And my opinion is the more leave you have between the two points the better your odds would be. That is to say the more leaves the more support the new roots would have.

If anyone has conflicting info please chime in. I am extremely new at this but I think I am on the right track here
(Or if they have more to add)

Two years ago i experimented with a pot designed for air layering which i purchased from Lee Valley. Thought the results may be of interest. I chose a shimpaku that had grown out too leggy and applied four at one time. All four took. Here are a couple of pictures to show the results.