Easy to grow and deer resistant, alliums add charm and whimsy to the late spring to early summer gardens. They're also excellent cut-flower arrangements. Sometimes called ornamental onions, alliums attract pollinators, too. Allium flowers are available in a range of heights and flower colors. The bulbs grow best when planted in well-drained soil and in full sun to partial shade. To improve your soil's drainage, mix in well-aged manure or compost. Alliums look best when they are planted in groups. Before buying allium bulbs, make sure they are suitable for your hardiness zone. Other factors to consider include mature height, flower size and color, and bloom time.