American Elm - Improving the Base - Airlayer or grafting

I have an American Elm that I am wanting to improve the base on. I know elm can be tricky to get a nice Nebari based on their circling roots, but I’m looking to try to improve it some how.

I know the 2 main ways to improve nebari is air-layering or thread/approach grafting. I’ve also heard that elms can be quite difficult for both of these techniques because of their rapid grown and callus formation. This tree was last repotted in Feb 2020 on a board in lava/pumice/cinder to help with some improvement, but probably should have been planted a little deeper into the soil to encourage root growth a little further up.

Does anyone have any good ideas? I’m in Los Angeles and I’m starting to get some bud swelling on some of my elms already.

1st photo is the front, 2nd is the back. Last 3 are from the repot in Feb 2020.

Looking at the amount of work to correct what’s there, I’d say that ground layering will be your fastest time to results. Start there and fill in gaps with grafts if necessary. Otherwise, you’re looking at sticking grafts almost all the way around and eventually removing any current roots that point in the wrong direction.

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I air layered a few elms last year and just repotted one of them today and was pretty excited about the great radial spread of fine roots. As long as you attend to the roots every 2 or 3 years after starting them off well, you shouldn’t have issues. They also only circle when the roots are growing in round containers. I have some elms with ugly roots, but none are circling except the ones I pull out of nursery pots.

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I would also advocate for an air layer. Knowing that elms and other deciduous trees can generate root mass so quickly I think you’ll be able to get better results this way.

I wanted to chime in about the soil mix. Have you considered using akadama? I know that these trees can be very thirsty and maybe even more so in LA. I feel that one of my biggest mistakes so far with deciduous has been sticking to pure inorganic (pumice). Curious to hear about your approach.

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I’d go with air layering, you’d probably get better results faster then with grafting all around the trunk.

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Thanks for the thoughts. I’ve got a few elm that were grown in oval and rectangular containers that the roots ended up circling the container and were a bit of a mess to deal with.

Thanks for the thoughts. I’ll be air-layering in a few weeks/month since Los Angeles got an early start on spring this year.

I haven’t used akadama to this point because I just couldn’t afford it till recently. I did get a good size bag over the winter and plan to use it for the layer and the future repotting. I’m hoping it will aid in the air-layer, as well as really improve the future development overall.

I did not have good luck airlayering with akadama or an akadama/pumice mix. Same tree with sphagnum moss worked very well. Your results may vary.