Tephrosia virginiana aka Catgut

Tephrosia virginiana is a perennial in the pea family. Its common names include goat's rue, catgut, and wild sweetpea. It grows wild in eastern North America. Its range reaches from Ontario and New Hampshire to Texas and Florida. It lives in dry woods, open glades, and sandy prairies. The name devil's shoestring refers to its long, string-like roots.

Garden plants reach 1–2 feet (0.30–0.61 metres) tall. They spread about 0.75–1.5 feet (0.23–0.46 metres) wide. The stems stand upright or sprawl into a mound. Soft white hairs cover the green stems and leaves. These hairs give the plant a pale, silvery cast. The leaves grow in an alternate pattern along the stems. Each pinnate leaf has paired, oblong leaflets and one end leaflet. The leaflets have smooth edges, with more hair beneath than above.

Small, pea-like flowers grow in racemes above the leaves. Their upper petals are pale yellow, sometimes tinged with pink. The wings and keel are rose pink. North Carolina State records flowers from May to June. Missouri Botanical Garden gives a longer season, through August. Green seedpods take the place of the flowers. They turn brown as they ripen and remain from July to October. Pods can reach 0.25 feet (0.076 metres) long. The plant draws bees, butterflies, moths, and birds. It also hosts northern and southern cloudywing butterfly larvae.

Full sun suits this plant best, though it tolerates some shade. It prefers acid soil with good drainage. Sandy loam suits it, with dry to medium moisture. Established plants withstand drought and need little upkeep. Its hardiness range covers USDA zones 3–9. Its deep roots make moving and dividing it difficult. Seed offers a way to start new plants. Yet Missouri Botanical Garden notes that seed growing can also prove difficult. Once settled, plants are best left in place. They suit border fronts, cottage gardens, and native plant gardens. They also add nitrogen to the soil. Missouri Botanical Garden reports no major pest or disease issues.

This plant is not edible, and its seeds are toxic. Its roots contain compounds used as insecticides and fish poisons. Sources differ on whether touching it can irritate skin. Plants For A Future warns of reactions in sensitive people. That source also records past medicinal and hair-washing uses. These records do not establish safe home use.