Hybrid tourniquet method?

[andrewiles]

I know ground layering and the tourniquet method have been discussed in numerous threads, but I haven't found any examples of what I've ended up trying. Curious what others think.

My understanding:

• Tourniquet method is slower than any layering that involves cutting the cambium, since the tree has to grow into the tourniquet to cut off nutrient flow.
• This method is safer, esp. for a ground layer with no leaves below, because the roots have no sudden loss of energy from the leaves and thus the tree has more time to grow out new roots at the layer.

As a newcomer I'd like to not kill off all the trees I bought so a gradual, safe approach is appealing. The scenario for me is that I purchased some vine and Japanese maples, all of which have a graft with an ugly bulge. I want to get them on their own roots right above the graft.

An appealing solution to me is to apply the tourniquet via a sheet of stiff aluminum with a center hole a few mm narrower than the trunk. A cut is made from one edge to the center hole, and as long as the sheet is flexible enough to be bent open while wrapping around the trunk, the net effect is a tight constriction once it's in place. By making the center hole a bit narrower than the trunk the sharp ends of the sheet cut into the bark and immediately begin constricting some, but not all, nutrient flow. Some rooting hormone is added at this point of contact.

I think this is likely to:

• Still be a bit safer than fully cutting the cambium
• Be faster than just using a wire without cuts
• Provide a flat base for the root growth once the top is separated.

Curious whether others have tried this or have opinions.

Example from my vine maple:

 

[leatherback]

I think @sorce does something like this, so he gets a good nebari straight away.

I personally doubt it is needed. MAYBE with very slow too root species. But for maples, I see no risk in just making the girdle?

 

[sorce]

That gel is hormone? Thought it was glue!

I don't know of the aluminum will win if it's creased. It may fold before it works.

I fear then it may cup up and hold too much water.

I believe I would have ringbarked that branch and buds off and layered there, just a CM up. I'd rub the small buds off as to not create a cinched "waist".

Keeping the rootstock?

Sorce

 

[andrewiles]

Yeah, may have been a bit generous with the rooting gel. I'm _certain_ doubling the amount of gel doubles the root development . I really don't understand why they don't sell this stuff in tubes. Be a lot easier to squeeze out in a confined space.

Good point on water retention. The sheet is angled down a bit so it should be ok. I'll know in a few months I suppose.

Wasn't planning on keeping the root stock since it's nothing special. We'll see once I'm able to separate the top.