Allium stellatum aka Autumn Onion

Allium stellatum, or prairie onion, is a bulbous perennial. It belongs to the Amaryllidaceae family. Its native range spans central and southeastern Canada into the United States. There, it grows in central and east-central regions. It lives on rocky prairies, slopes, shores, and ridges. Many sites have limestone soil. In Missouri, it grows on Ozark glades and bluff ledges. It is not native to Britain or Ireland.

Garden plants reach about 1–1.5 feet (0.30–0.46 metres) tall. Their spread reaches about 1 foot (0.30 metres). They form upright clumps of narrow, flat, grass-like leaves. The leaves can reach 1 foot (0.30 metres) tall. Both leaves and flower stems grow straight from the bulbs. The flower stems have no leaves and rise above the foliage. Small reddish-pink flowers form round umbels at their tips. Each bloom has a star-like, bell-shaped form. Flowering runs from July to September in Missouri Botanical Garden's account. Chicago Botanic Garden also lists bloom into October. Leaves may fade at flowering or persist a little longer. They die back by late summer.

Prairie onion grows best in full sun and well-drained soil. It also accepts light shade. Afternoon shade can help in places with hot summers. Rocky or sandy ground suits it best. It grows in average soil with dry to moderate moisture. The plant tolerates drought, dry soil, and shallow rocky ground. Missouri Botanical Garden also lists tolerance of black walnut. Both garden sources give USDA hardiness zones 3–8. Care needs are low, with no serious insect or disease problems reported.

Use prairie onion in rock gardens, borders, or native plant beds. It also fits meadows, cottage gardens, and areas left to naturalize. Its flowers add summer color, and deer tend to avoid it. Plants spread through seeds and offsets from their bulbs. Remove spent blooms before seeds form to limit unwanted spread. Sow seeds in spring or plant bulbs in autumn. Division offers another way to raise more plants. Allow for bare space when the leaves die back.

Plants For A Future lists bulbs and leaves as edible, raw or cooked. It also lists raw flowers for use in salads. The bulbs are small. The same source records a sweetened root decoction used for colds. This describes past use, not proof of benefit. It also records plant juice used to repel moths. It provides no species-specific poisoning report, so safety remains uncertain.