Culinary members of the onion family include onions, shallots, leeks, chives and garlic, but there are also many ornamental species and cultivars grown for their showy spherical flowers.
Ornamental alliums vary from alpines only a few centimeters tall to stately giants that reach more than a meter in flower, such as A. hollandicum ‘Purple Sensation’, A. ‘Globemaster’ and A. ‘Gladiator.' Plant these versatile performers with roses, in grass borders or behind low hedges. Reaching 45-90cm, medium-sized alliums such as A. atropurpureum, A. christophii and A. sphaerocephalon go well with silver-leafed Stachys byzantia or Artemisia ‘Powis Castle’.
Smaller plants such as A. cyathophorum var. farreri and A. moly like cooler, more moist conditions than larger alliums and are well suited to rock gardens or pots. For the front of borders, low-growing A. karataviense has broad, glaucous leaves. The color range is dominated by shades of purple and mauve, but there are selections with flowers of white, blue, yellow, violet or deeper purple.