Depending on whether you're prone to planting flowers or vegetables, you may associate the word "allium" with the savory flavor of garlic, onions, shallots, and chives. Or, you may picture stunning umbels of pollinator-attracting flowers. They're all related, of course, but theses allium seeds have been bred for their showy blooms. Alliums are vigorous perennials that prefer full sun and well-draining soil. The seeds require cold stratification.