Double decker air layer on cryptomeria – Bonsai Tonight

January 9, 2018 by Jonas Dupuich

I’ve always been curious about whether a double air layer could be used to produce three trees at once. Knowing that cryptomeria bonsai layer well, I thought I’d give it a try.

Double decker air layer started May, 2017

One challenge I had was that there was little foliage between the two layers. It’s better to have more foliage as the more growth, the more successful the root production.

Small gap between layers

I could see roots inside the plastic on the top layer so I figured it would be safe to remove it. Here’s what it looked like inside last week.

Roots growing in white sphagnum moss

It turns out most of these roots emerged from just one side of the trunk.

Few roots on the other side

There was good callus all the way around so I reopened the callus where there were no roots and reapplied rooting hormone to help stimulate new roots in this area.

What about the lower layer? Here’s what I found inside.

Good callus, few roots

Clearly, it was not yet time to remove the lower layer. I cut away the bottom half of the callus, reapplied root hormone and filled the bag up with a mix of moss and bonsai soil.

All closed up

Were there more foliage between the layers, I’d guess there would be more roots. Will check the bag again in a few months to see how the new roots are developing.

The remaining layer

As for the section I removed, I pruned it a bit to remove an extraordinary number of pollen cones.

Cryptomeria pollen cones

I then planted the layer in a standard mix of bonsai soil (akadama, lava, and pumice).

Because young roots are weak, I used the tie-down wires to secure the tree directly rather than using the wire to secure the roots.

In the new pot

The side with no roots

Here’s the separated layer in its new pot.

Cryptomeria from air layer – January, 2018

It’s essentially a large rooted cutting at this point so I’ll be watching the water carefully for a while.

What about the split trunk about two inches above the soil line? Looks like a good opportunity to create a twin-trunk specimen. The now obvious second trunk was a small shoot last year or I would have started the layer higher up. I’ll look to re-layer the tree in another year or two once it’s better rooted in to its new pot.