Dark, silvery purple baseball-sized blooms on 24- to 30-inch tall stems characterize Allium ‘Firmament’. For naturalizing, this cultivar is best grown in full sun in sandy/gravely soils that remain dry from midsummer through fall. Alliums attract a number of pollinating insects, including butterflies, moths, and bees. Chipmunks, rabbits, and deer find the strong onion flavor of the flowers, leaves, and bulbs objectionable. Gardeners often interplant ornamental onions between their crocus and tulips in an effort to deter herbivores.