Trifolium hybridum aka Alsike Clover

Trifolium hybridum, or alsike clover, belongs to the bean family. Its native range stretches from the Mediterranean to Iran. It also reaches southeastern European Russia. European settlers brought it to the United States. It now grows beyond gardens across the Americas. It occurs in damp meadows, pastures, old fields, and roadsides. Sources describe it as perennial, though Kew also records annual plants.

The plant grows fast, with upright or rising stems. Its green stems are hollow, round, and free of hairs. Some stems branch, but they do not creep and root. Green compound leaves grow in an alternate pattern along them. The leaflets have no pale markings. Their smooth surfaces contrast with their fine, toothed edges. Their shapes range from oblong to broader near the tip. The plant has a fine texture rather than coarse foliage.

Round heads of white and pale pink flowers appear in summer. Each head holds about 30 to 50 small florets. The pink deepens as the flowers grow older. Lower flowers darken first, giving each head two shades. The heads rise on stalks without leaves beneath them. Bloom lasts for a long season. Short, broad pods follow the flowers in summer. They start greenish brown and become almost black with age. The ripe pods stay closed rather than splitting open.

Alsike clover grows best in cool, moist conditions. It prefers full sun and moist soil with good drainage. It also grows in part shade and tolerates dry soil. Clay, loam, and sand can all support it. It accepts acid to neutral soils, including poor ground. North Carolina State lists it for USDA zones 5–9. Gardeners can raise new plants from seed. Root bacteria fix nitrogen in nodules, helping enrich the soil. People grow it for pasture, hay, and beneath orchard trees.

Its flowers draw bees, butterflies, and other pollinators. Clouded sulphur caterpillars use it as a food plant. Birds and mammals also eat its seeds and leaves. It can become weedy and fares poorly with frequent mowing. Aphids may attack its flowers and foliage. It can harbour mites that harm gooseberries and camellias. PFAF records edible leaves, flowers, and seeds, including tea and flour uses. This does not establish safety for animals. The ASPCA identifies it as poisonous to horses. Reported effects include sun-related skin injury, ulcers, and liver failure. The toxic substance remains unknown.