AusBonsai

I'm trying to air layer a silky oak. I have tried three times, at different times of the year. Each time it callouses over and doesn't form roots. I am ring barking with spagnum moss. I have tried with and without rooting hormone, and with a wire tourniquet. I understand the basics and I have air layered other species. There is a thread here where it has been done.

Does anybody have practical experience that might help me get this to work?

Cheers,
Symon

I don't have practice experience of Grevillea robusta to offer. I do have a couple of questions though.

When you say callus over, do you mean callus from the top and the bottom meet in the middle? Or has the whole area formed callus?

I ask because I have had an air layer form callus over the whole area like it was trying to produce bark again. I though I had removed all the cambium but wondered if the where still some cells there. I cut the area a little deeper, scrapping some of the outer sapwood off and it then was successful. Ive also seen a large area of bark knocked of a large Eucalypt by a bobcat that formed callus over the whole area within a few weeks and bark up again within a few months.

So I suppose the last question is how deep did you cut?

Hey Dansai, good question. Yes I have cut deep enough the callous comes from the top and bottom.

Cheers,
Symon

Well the next question would be what type of root hormone did you use? There are different ones for softwood and hardwood. I haven't looked into the differences but I assume a hardwood one would be more suitable for air layering rather than a softwood one that would suit cuttings. There was a member on here some time ago that did a lot of research and sharing of his experience who had great success air layering Black Pines (Notoriously difficult) and some hard to air layer Japanese Maples. He used a combination of a gel and powder to make a paste that he applied to the top cut, used wire tourniquet, then applied more hormone and some muck before wrapping in sphagnum. He also said it was important to make sure the sphagnum wasn't too wet.

Good luck and I hope for your success.
Dan

Hey Dan,
I used the one with the higher concentration of the indole acetic acid.

I think you just dropped some gold. My spagnum has been very wet. As you know Coffs has been drenched this summer. I wonder if I keep it a little on dryer I'll it will work?
Cheers
Symon

Some pictures would be good.

I had the same issue with a trident years ago, first attempt it reconnected, was crazy, disappointing but very impressive ... Think the tiniest, thinnest, microscopic cambium was left on, in a part that was tricky to access (around the back).

Subsequent layers were successful, plus yes, I used the "yates powder plus purple clonex" mix and lots of barely damp sphagnum.

Maybe try on a different branch too?

Here is a pic of the latest attempted layer. It is very wet, we have had 400+ mm of rain in the last few weeks. I am dubious of using rooting hormone. I use it to promote callus on hard to heal scars. There is a misunderstanding about how it works. It doesn't by itself induce root growth rather it is an interaction between the indole acetic acid (the active ingredient) and other phyto hormones like cytokinins. For example, I find crepe myrtle layers work best without it. But at this point I will try anything!

Here is the trunk I want for a group planting. The angle makes it look like there is no taper but it is actually quite good. And here is what I want it to turn into... Just jokes.
Cheers,
Symon.

Yes the layer does look very wet, maybe tape up the top better and or cover the plastic with foil. The length of where you have cut down to cambium looks a bit short given the thickness of the branch, of the ones I have done length is usually about 1.5 x the branch thickness.

I have also used honey, as I believe it stops bacteria growing.

How thick is the branch as this may also play a factor in success rate.....

There are some good threads on here about air layering.

I'll try tape thanks for the tip.

Cheers,
Symon