Thaspium trifoliatum aka Purple Meadow Parsnip

Thaspium trifoliatum belongs to the carrot family, Apiaceae. It is a perennial, which means it lives for years. Its common names are meadow parsnip and purple meadow parsnip. It grows wild in the eastern and central United States. Its range runs from Minnesota and New York to Texas and Florida. Many groups grow in the Mississippi River valley. Wild plants grow in prairies, woods, and thickets. They also grow on stream banks and rocky slopes.

Plants grow upright and branch on ridged stems without hairs. Garden plants reach 1–2.5 feet [0.30–0.76 metres] tall. They spread about 1–2 feet [0.30–0.61 metres]. The stems may be green or tinged with purple. Leaves near the base have a heart shape. Most of these basal leaves have one whole blade. Leaves on the stems split into three toothed leaflets. These leaflets are oval and have pointed ends. Both sides of each leaf are green and have no hairs. Stem leaves grow in turn along the stem, an alternate pattern.

Small flowers grow above the leaves in compound umbels. In these clusters, each main umbel branches into smaller flower groups. NC State describes the blooms as reddish-purple. Missouri Botanical Garden reports yellow blooms. Plants bloom from April through June, though timing varies by place. NC State gives a bloom span of three to four weeks. The tiny flowers have five petals that curve inward. Small, oval fruits follow the flowers, with wings on their sides. Each fruit has two parts, each with one seed. Fruits form in summer and may stay into fall.

Grow this plant in moist soil that drains well. It accepts clay, loam, sand, and soil with some rocks. It can also grow in acid, neutral, and alkaline soil. Missouri Botanical Garden calls for full sun or part shade. NC State also notes wild plants that grow in shade. The listed hardiness range is USDA zones 3–9. Plants grow at a moderate rate and need little routine care. Seed is a listed way to raise new plants.

This plant suits woodland beds and native plant gardens. It also fits areas left to grow wild and gardens for pollinators. Its flowers draw butterflies and other pollinators. Black swallowtail caterpillars use this plant as a host. Neither garden source reports serious problems with pests or disease. Plants may be hard to find at nurseries. The supplied sources give no guidance on food use or toxicity.