Interesting, Maggi. Looks like the plant in the photo at Denver Botanical Garden is a whole lot taller than the 20-25cm in the associated description, though. (And I'll bet it's hardy well below zone 6, too!)
Sorry, nothing useful to say about distinguishing it from E. ritro (though I should go out and take a look...)
This posting caught my eye as I grew Echinops tschimganicus from seed years ago, and I used to wonder about the validity of that name and thought I detected some similarity just now to "tjanchanicus". However, I see that the Plant List considers both to be accepted species.
