Cliff Onion
Allium stellatum
Lily family (Liliaceae)

Description: The Cliff Onion is a native perennial plant. It has relatively few basal leaves that are linear, flat, solid rather than hollow, and about ½-1' in length. They tend to recurve outward from the base of the plant.

The flowering stalk emerges among the leaves and is about 1-1½' tall. It is more stiff than the leaves and remains erect. The attractive flowers are arranged in an umbel at the top of this stem – this umbel is about 2-3" across. Each flower is white, light lavender, or pink, depending on the local genotype, and is shaped like a small star with 3 petals and 3 sepals that flare outward. Each flower is slightly more than ¼" long. The blooming period occurs during late summer for about 3 weeks, by which time the basal leaves will have died down if the weather has been dry. The entire plant has a typical onion-like smell. The root system consists of a bulb with unusually deep secondary roots for such a small plant. This, no doubt, promotes survival during dry weather. If conditions are favorable, the Cliff Onion will slowly cluster at the base, or reseed itself.

Cultivation: The preference is full sun and dry conditions. The soil should be rocky, rather limey, and well-drained. However, this plant will grow in ordinary garden soil and average moisture conditions if competition from taller, more aggressive plants, is eliminated. The Cliff Onion is slow growing, but easy to establish, if the preceding conditions are satisfied, otherwise it is likely to become lost in the surrounding vegetation.

Range & Habitat: The Cliff Onion is a rare plant in Illinois, occurring in only a few counties, primarily along the Mississippi River in the SW region of the state. Natural habitats include rocky limestone bluffs and cliffs along rivers, limestone glades, and hill prairies. This plant occurs in more ordinary prairies in areas to the west of Illinois because of the drier conditions.

Faunal Associations: The flowers attract small flying insects, primarily flower flies and small bees. Most native herbivores probably do not feed on this plant because of the onion scent and spiciness of the leaves. However, livestock are known to eat the foliage of native onions along with the grass in pastures.

Photographic Location: The above photograph was taken at the webmaster's wildflower garden in Urbana, Illinois.

Comments: The Cliff Onion has a delicate beauty when in bloom, resembling a starburst effect. Sometimes this plant is called the 'Prairie Onion,' however it is more typically found along rocky cliffs and limestone bluffs near rivers in Illinois. The foliage and bulb of this onion are edible, if somewhat strongly flavored. The Cliff Onion differs from Allium cernuum (Nodding Onion) by its more erect inflorescence and slender leaves. It resembles Allium canadense (Wild Garlic), but doesn't produce any bulbets in the infloresence. The Allium spp. from the Old World, such as Allium vineale (Field Garlic), have round hollow leaves, while those of the New World have flat solid leaves.