Trifolium wormskioldii aka Cow Clover

Trifolium wormskioldii belongs to the pea family, Fabaceae. It is a perennial, so it lives for years. People call it cow clover, springbank clover, or slender clover. Its native range runs from western Canada to Mexico. It grows in mild regions, from beaches to mountain meadows. Wild sites include coastal dunes, stream banks, and wet meadows. It grows in salt marshes and brackish marshes, too. Some sites flood from time to time. Its range reaches about 10,500 feet [3,200 metres] above sea level.

This plant has soft stems and a creeping rootstock. Its stems branch and may stand up or creep along the ground. One account lists its height as 0.3–1 foot [0.1–0.3 metres]. Stems can grow 2.6 feet [0.8 metres] long. A separate size entry lists a height of 3.3 feet [1 metre]. That entry gives a spread of 1.6 feet [0.5 metres]. The plant grows long, fleshy, white rhizomes, or stems below ground. It keeps growing tender leaves later into summer than some other clovers. These are other edible clovers of western North America.

Grow cow clover in full sun and moist soil that drains well. It accepts wet ground but cannot grow in shade. Sand, loam, and clay can all suit it. It can grow in poor soil and salty ground. Its soil pH range runs from slightly acid to strongly alkaline. For garden use, soil close to neutral suits it. The source lists USDA hardiness zones 5–9 and notes that it tolerates frost. To help keep plants growing, divide them every three or four years. Spring is the best time to divide them.

Insects pollinate the flowers; the plant cannot fertilise itself. It fixes nitrogen, giving it a use beyond food. To grow seeds, first soak them in warm water for twelve hours. Sow them outdoors in spring, or start them in pots. Plant young plants out after the last expected frost. The source does not class this species as invasive.

Several Indigenous peoples of North America managed cow clover for its rhizomes. They prized the long rhizomes more than the short taproots. They ate roots raw or cooked, often after drying them. Reports list leaves, flowers, and seeds as foods, too. Take care: eating this plant can cause bloat. Eating more raises that risk. The source also warns of compounds that may cause harm. It does not name them. It records no known use as medicine.