The ornamental alliums are a diverse group. There are tall growers with dense globes of starry flowers that are held well above the leaves and ground huggers whose colorful blooms open in small clusters. All demand well-drained soil and plenty of sun (afternoon shade will prolong bloom in warm climates) and flower at the end of the spring bulb season, after the tulips are done.
The genus Allium includes a number of familiar edible plants: onions, garlic, leeks, chives and shallots are all alliums. When you sniff the bulb or bruise the foliage of an ornamental allium, you will immediately think “onion!” People have long appreciated the flavors offered by this group, but deer find them distasteful. You can plant alliums in deer country and rarely observe a nibble.