As promised for Dom, here are some photos of the fine American Allium,
A. plummerae. It is a high elevation species found in a limited range in Arizona and New Mexico, USA, growing in moist alpine meadows. In good garden soil in full sun, it is among the most all-around ornamental species, making dense clumps of silvery-bluish foliage, fine upright-facing domes of pure white flowers starting the end of July, flowering throughout August. With age, the ovaries age to yellowish, orange, or pinkish... very nice. I've never had self-sown seedlings appear.
Happy Holidays all