I think i saw the seeds in thompson & morgan catalog

That's were I've seen Chocolate Cosmos seeds too...Thompson and Morgan. They have a great selection of seeds so it's well worth the trip there on the web. But I'm sorry I don't have the URL for them. Good luck

Both the 2000 Park Seed catalogue and the 2000 Wayside Gardens catalogue list Chocolate Cosmos, but unfortunately both sell small plants and not seed.

I think that's because Chocolate Cosmos are best grown from tubers. I tried the seeds offered by T&M and they are not the chocolate cosmo that my friend in Seattle grows. The other interesting tidbit is that they need moist soil so that sort of eliminates them from my garden. But I would like to try them in a container where I can more easily provide the conditions they want. I am going to spring for the plants from the Wayside catalog.

I live in zone 8. It is hot and dry here. I have since moved my plant and purchased 2 others and put them in the only garden that I keep moist, as I have clay soil, but that garden has been amended with quite a lot of humus. Yes, they really respond well to moisture, and I don't dig them up in the winter. I just leave the pine needles that fall on that area for a protective mulch. It snows here in the winter, but I can't rely on that for a mulch. Then I remove the needles in spring. It has early morning sun, then shade mid morning, then hot sun until the afternoon, then it is shady after that.

I have just planted two tubers in pots (in damp medium) and am wondering how long I should expect to wait before I see any green growth.
Any clues? Thanks.

i planted 3 tubers (from park's seeds) in a container on my back patio. they didn't do much for a few weeks, but they they steadily grew and leafed out and i've got a profusion of buds and a few lovely flowers now. i'd say it took about 2 months from planting to flowering.