I bought this lovely Japanese Maple at my local nursery the other day :-).
It's a lot more mature than the saplings I've been having so much touble
with - about 5' high and about 1cm diameter at the base. It looks very
healthy , just a touch of mealy bug which I've already sprayed for.

I'm going to chop it at some point, but would like the trunk to get a bit
thicker first. In the mean time I want to get a few more plants out of this
nice tree. Everything I've seen here leads me to beleive that it is
notoriously difficult to get cuttings from A. Palmatum to strike. How about
layering? And what about multiple layers from the one trunk? I'd like to
make this one tree into 3, and get some variety of forms - single trunk at
the base, and probably 2 dual trunks higher up, making branches into
secondary trunks by layering just under them. What's the best way to go?
Should I layer higher up the trunk, let the tree recover for a year then
layer off again lower where I want the first chop? Or would it be better to
layer it lower down, where I want the first chop to go, then repot the
layered tree and layer that one again later?

Also, what's the best medium for layering A. almatum? (And the Liquidambar
for that matter, I forgot to ask). Would sphagnum moss work, or some other
medium?