Dalea purpurea aka Purple Prairie Clover

Dalea purpurea is a perennial wildflower called purple prairie clover. It belongs to the bean family, but is not a true clover. Its native range spans central Canada and much of the central United States. It grows in prairies, rocky open woods, and glades. In Missouri, it occurs across most of the state. This plant helps restore prairie land by adding nitrogen to soil.

Garden plants reach 1–3 feet [0.30–0.91 metres] tall. They spread 1–1.5 feet [0.30–0.46 metres] wide. The plant has an upright form with stiff, wiry stems. Its green stems are hairless and have slight ridges. Older plants develop more branches. Dark green leaves grow in an alternate pattern along the stems. Each pinnate leaf has three to seven narrow leaflets. A thick, woody taproot reaches 5.5–6.5 feet [1.68–1.98 metres] deep. This deep root helps the plant cope with drought.

Small purple flowers crowd into spikes at the stem tips. The spikes have a cone-like shape and golden-orange anthers. Flowers open first at the base, then progress upward. Most sources place bloom from June to August. Chicago Botanic Garden also reports flowers as early as May. A plant may flower for four to six weeks. Bees, bumblebees, and butterflies visit the blooms for nectar. The leaves feed caterpillars of two butterfly species. These are Dogface Sulphur and Reakirt's Blue. Small legume pods follow the flowers and hold one or two seeds. The seeds ripen in late summer.

Grow this species in full sun and soil that drains well. It accepts sand, loam, clay, and rocky ground. It also tolerates acidic, neutral, and alkaline soils. Soil can range from moist to dry. The plant withstands drought and suits USDA zones 3–8. It grows at a moderate rate and needs little upkeep. Sources report no major problems with insects or disease. Plants may seed themselves when conditions suit them. Seed is the recommended way to raise new plants.

Use purple prairie clover in borders, rock gardens, and meadows. It also fits native gardens and broad prairie plantings. Its roots and soil-building role support land repair and erosion control. Grazing mammals eat the plant as a protein source. Native Americans boiled its leaves for food and tea. They also chewed the roots for their taste. Roots may taste sweet, but can be fibrous or woody. Traditional uses include leaf poultices for wounds and stems for brooms. These food and medicinal records do not establish general toxicity safety.