M5, I've been really enjoying my Amur maples too! I have several mame sized trees that I just began working this spring. And I have a couple larger ones; one reduced from a 15 gallon nursery can to a shallow bonsai pot this spring.
Here are a few native plants I collected this spring for Kusamono.
First up are a couple of Sedum Lanceolatum, or Lanceleaf Stonecrop. First is in a Bigei, and second in a Sara Rayner.
Beautiful kusamono Dan! I'd love to see your amur maples! I have another one that's a short and thick multi trunk stump that I'm excited to tackle next spring.
I really love this tree. If it were mine I would seriously consider reducing down the foliage mass and define some foliage pads of a sort. Nice job on what I consider to be a difficult tree.
Here are some shots I took of my Korean Maple (A. Pseudosieboldianum) 'North Wind' this spring. I believe it may actually be a cross between A. Pseudosieboldianum and A. Palmatum, but I'm not sure. Anyway, this is a yard tree, but I will certainly try an air layer or two for bonsai. These are proven hardy to Zone 4 and possibly colder. I have a species KM that I've had in the yard going on 4 years now, and It's done great in our harsh climate.