Irises grow from tubers. If you can get a few tubers from someone, don't plant them very deep and they should take off for you. Often people have irises for years and they are all grown together in thick clumps and thinning them out will help them create better blooms. Maybe you can find someone with some irises in need of thinning and you could do that in exchange for a few tubers?

I have some Japanese Anemones that really grow like crazy. I thinned mine out last year, and don't need to get rid of any, but you might be able to find someone in your area that could be in need of thinning theirs out. They really grow fast and spread underground as well as go to seed.

Have you tried http://www.kitazawaseed.com/ ?

They sell Japanese seeds in the US. I bought various ones.

Ganbatte Kudasai!

Miwa