Somehow it seems wrong that no one has posted on this rather important little genus...
I don't have pictures of Eritrichium pauciflorum on this computer...I will post on that some time. It was the universal forget me not of the Mongolian mountains that grew by the thousands in all manner of turf and meadows, screes and tundra..I did get quite a bit of seed of it and shared it with some alpine nurseries. I have a fantasy it will be an easy alpine.
But for us in Denver, Eritrichium howardii is the one of choice: up by Choteau and here and there on the Great Plains of Montana (in a climate very similar to Denver) this grows thickly in the sparse grasses. Roy Davidson wrote of one locality where it was virtually the only thing growing for miles where cattle were browsing: he wondered if it was their fodder?
This clump has graced this trough for almost ten years, petering out a bit one year, and coming back the next. It has produced a finer display of bloom, but this is all I have on hand right now...so you must settle for it!