Reaching a height of 18" - 26", Allium pulchellum will gently self sow itself into nice little drift, and seedlings reach flowering size in just about a year or two.

By the way, the specific epithets, pulchellus, pulchella, pulchellum, mean "somewhat beautiful" or "pretty" according to Chuck Griffith's monumental work on the subject of specific epithets

I've isolated a pure white cultivar and hope to make it available in the next year or so. In the meantime, I've plenty of the deep pink species in 2" tree band pots ready to fly out the door in full flower.