Barbarea orthoceras aka American Yellow Rocket

Barbarea orthoceras is a flowering herb in the mustard family. Its common names include American yellowrocket and wintercress. Kew records its range across temperate Asia and subarctic America. It extends south to Baja California in Mexico. In North America, it grows beside streams and in wetlands. It also occurs in forests, mountain meadows, and disturbed ground. It grows as a biennial, though some plants live longer.

Plants reach 1–3 feet (0.3–0.9 metres) tall when flowering. Their spread is about 0.7–1.3 feet (0.2–0.4 metres). A young plant forms a low rosette of glossy green leaves. These lower leaves have deep lobes and a larger end lobe. Leaves grow smaller farther up the stem. Their edges may be wavy, toothed, or smooth. One or more upright stems rise from the base. The smooth stems have ridges or angles and purple-green streaks. A stout taproot makes mature plants hard to move.

Small yellow flowers open from May to June. Each flower has four petals and four greenish-yellow sepals. Flowers form clusters at branch tips and in leaf axils. They have a scent and attract butterflies. Butterflies, skippers, and moths also feed on the plant. The fruit is a narrow seed pod called a siliqua. Pods reach about 0.17 feet (0.05 metres) long. They stand upright or angle upward, sometimes with a curve. They turn brown as they dry and expose their seeds.

Grow this cool-season plant in sun or light shade. Keep the soil moist, but allow excess water to drain. It grows in loam, clay, sand, and rocky ground. Sources support acidic through slightly alkaline soils. NC State lists USDA zones 3–7; PFAF suggests about 3–8. Summer heat can end its growth. NC State reports poor performance in the southeastern United States. Seed is the recommended way to raise new plants. It needs little upkeep and grows at a moderate rate. It suits rock gardens, native beds, meadow borders, and pollinator gardens.

Young leaves provide a sharp spring green, raw or cooked. PFAF also lists young shoots and unopened flower clusters as food. Older growth becomes less useful for cooking. Eat leaves in moderation; NC State notes possible kidney effects. PFAF also flags concerns for people with thyroid problems. ASPCA identifies the plant as toxic to horses. Its isothiocyanates can cause gut irritation and colic. Mustard-family insect pests may attack it. PFAF flags weed potential and lists no known medicinal use.