First time posting in a forum so forgive the ineptitude, also I don’t check the forum very often, if you ask me questions it might be a while before I reply, sorry
I’ve just been watching the companion planting stream, very good, very interesting, there was a question about sourcing plants, in America there is a good source of seed.
I’ve just order seed from Alplains.com, this is a man who collects seed from varies terrains within America, his seed list is extensive and there are many dwarf forms, which might make good accents in their own right, but plenty of variety for your Kusamono.
He provides a legend on germination details, which is so useful, I finally made an order this year after hearing reports, from well know growers here in the United Kingdom and Swedish growers about variety and quality of seed.
Unfortunately new laws are coming out in America this January which will make it difficult for him too export, but in America you should fill your boots before he retires.
What I know of him, he sounds like a Mirai kind of guy, a person with a passion, who does it for the love of it.