Oak Air Layer aftercare help?

[keegan]

Hi there!

I live in Los Angeles.

I air-layered a cork oak. Layered March 2017, checked for good roots in Oct and again in January.

Finally split March 1, 2018 with some good roots in a small-fist-sized ball of sphagnum.

I planted the top in a new pot with well draining but not super-airy bonsai soil. I did not trim anything from the top.

After 3 weeks it is March 22nd, and the leaves are going yellow. It has been rainy most of March and the pot has never dried out fully.

And so, my questions:

1. Is it normal for the tree to drop all its leaves during this time? So, nothing to worry about?
2. Should I have cut back the top leaves to reduce transpiration (but as I said, it has been humid and rainy).
   2a. Should I cut the top back now?
3. Should I have potted it in something with more oxygen, more porous and root-stimulating, like pumice?
   3a. Should I take it out and do that now?
   3b. The reason I ask is that maybe it has been too moist and the roots are rotting?

Thanks in advance for any advice! See attached pics of the top (yellowed leaves) and the bottom (leaves look good).

Cheers,
Keegan

cross-posted in layering forum

 

[BrianBay9]

I've never tried air layering an oak, but I'm told it's common for collected live oaks to lose all their leaves after collection, then bud out again.

 

[0soyoung]

Regardless of species, the two main problems I've encountered with freshly harvested air layers are

1. securing the tree to the pot so the roots don't get disturbed by the wind or one moving it around
   1. roots generated in sphagnum are mechanically weak, easily broken, and cannot be used to secure the tree
2. being sure an adequate amount of roots have been created to support the layer before it is harvested

I would venture that you have committed one or both of these sins, but it could be something more 'sophisticated'.

In either case, the likely problem is that the tree is loosing water to transpiration than can be taken in via whatever roots its got. Best hope is to minimize this loss. Keep it in shade. Build a humidity tent, that is, build a terrarium around it. Be patient.

 

[Bonsai Nut]

Too early to panic. When you separate an air-layer, you have to treat the tree like you are doing an emergency repot. You need to use the best soil, make sure you anchor it really well (since it has almost no roots), and protect it from too much sun or wind.

At this point, I would just continue to protect it and see what happens. Any additional work (i.e. changing soil, etc) would probably do more harm than good. Roots shouldn't be rotting if you put it in new soil less than a month ago.

 

[sorce]

Welcome to Crazy!

Sorce

 

[keegan]

I don't know how this ended up in the Elms sub-forum. Sheesh, I must have had to much wine. Sorry about that.

I talked to Ted Matson, a local bonsai sage, and he said leave it, let it get good and dry between waterings, and see what happens. A couple others echoed these thoughts, so that's what I'll do.

Thanks everyone!

 

[M. Frary]

let it get good and dry between waterings

Obviously to make the roots search for water thus getting stronger. The only problem with that is you're trying to walk a fine line. I might let it get a little dry but not good and dry.

 

[aframe]

Is this occurring on last spring’s growth?
Are the buds swelling?

 

[keegan]

Not sure how this ended up in the Elm forum (sorry for that, maybe a moderator can switch it?), but I'll post the update here in keeping with the thread. As you can read above, the top of my air layer was definitely a goner, but...

In March, a single oxalis weed grew with 4 leaves--a lucky sign? I figured, what the heck, let's try one more thing...

I potted it into a small container with 100% pumice. When I took it out to repot, there were no roots, just a lot of callous. I left it and gave it time.

Low and behold! June 3rd, a bud sprouted! By June 18th I had a full branch of buds. Now it's July 6th and still only two branches have a few leaves, and the rest of the tree still seems very dead. But we'll just keep waiting!

Never give up!