Planning a ground layer

I’m planning on doing a ground layer on this Siberian elm this year. The roots are super coarse and I want to get rid of the inverse taper and shorten the trunk a bit; all good reasons for a ground layer. I will wait for the first flush to harden, but should I leave all of that foliage and let the tree grow unchecked as I initiate the ground layer? It seems like that would help stimulate new root growth, but this will be my first attempt and am wondering if I’m missing anything.

Below is a pic of the tree to be layered, and below that is the start of a Siberian elm forest. I have about a dozen smaller trees I’ll add next year. Trashy and invasive trees in the wild, but indestructible and kind of nice as bonsai. I started all of these from seed and ground grew them a while.


I assume you mean air layer, or do you plan to plant this back in the ground? But either way, I’ve heard Ryan say you want as much foliage strength as possible to drive new root production (addressed this on a recent Q&A but don’t remember which one), so I’d fertilize heavily and then let it run free before air layering.

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I agree with @Tac about fertilizing and letting it grow. I have done layers close to the put surface as you are proposing and my approach is:

  • Cut the ring for layering.
  • Build a ring of screen or small mesh around the trunk at 4-5 times the trunk diameter that is taller than layering location.
  • Fill the bottom of the ring with coarse pumice or lava so water will flow through it to just below the bottom of the layering cut.
  • Place a layer of weed block cloth on top of the coarse soil.
  • Add a thin layer of appropriate bonsai soil.
  • Wrap the layering with damp sphagnum.
  • Fill the remainder of the ring with soil.
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Got it, thanks for the detailed advice, @MartyWeiser

Sweet, will do @Tac . I thought ground layer was the term for basically an air layer that’s right above the current root system, with the pot/bundle containing the new roots resting on the soil surface. But maybe not!

I thought I remembed Ryan did this same thing (layering above the roots) in a video about “air layering,” but who knows. Just semantics, but wanted to make sure I understood what you were planning to do, because if you were going to put it in the ground, I was going to recommend waiting a year after planting it to let it take. But since you’re not doing that, the previous recommendation holds.

Good luck!

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Hi Brad, as recommended by others, definitely let the tree grow freely and fertilize well to encourage the layer to root. I’ve done a number of layers such as this on various material to get rid of bad nebari or ugly graft unions. I also normally put weed block cloth on the soil in the pot to keep the new roots from growing down into the existing pot. I use a plastic nursery pot of an appropriate size for the layer, just cut the bottom out and shorten it to the desired height, then cut the wall vertically so you can slip it around the tree. I just use duct tape to hold it together. Make sure you scrape well into the trunk when you cut the ring of bark so that you don’t leave any of the cambium that will heal over. You might want to put some rooting hormone on the upper cut edge. I then just fill up the pot with akadama. I don’t recommend putting any sphagnum around the layer site as it will stay too wet when you water the tree during the year. Also, once you water the layer, don’t water it again until it gets on the dry side, and then don’t water too much until you see some evidence of new roots. You’ll probably see some roots escaping around the bottom of your nursery pot as it starts to fill with new roots from the layer.

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Nice, I like the weed cloth idea. Thanks!