Q.Jade Plant
Six months ago, I took my 40+yr old jade tree and separated it into 5 substantial plants. I was able to preserve the roots and only separated what was underground. Once each plant had its own room to grow, they took off. One branch, (36” long, and 8” around at its juncture,) above ground, has vectored off and is effecting the whole plants stability. I wonder if I can air layer the branch a couple inches above the juncture? There is great new growth at the top of the branch I want to save, and it would make a great new plant. What mixture would I use in the container I am layering in?

Certified GKH Gardening Expert
I would use, either, a seed starting mix, or some inert mix such as Pro-mix, that has no nutrient content. You could also add a rooting hormone into the water that you will moisten this with.
I could also suggest using a plastic wrap to layer sections. This requires very little soil, and is a very stable method of layering.