Cardamine concatenata aka Cut Leaf Toothcup

Cardamine concatenata is a perennial wildflower in the mustard family. Its common names include cutleaf toothwort and pepper root. It grows in eastern Canada and the central and eastern United States. Wild plants live in rich woods and on wooded slopes. This spring ephemeral flowers before trees open their leaves. Its leaves die back by late spring or early summer.

Garden plants stand about 0.67–1.25 feet (0.20–0.38 metres) tall. Some plants reach only 0.5 feet (0.15 metres). They spread about 0.5–1 foot (0.15–0.30 metres) wide. Upright, unbranched stems rise from underground rhizomes. These rhizomes have linked sections and toothlike bumps. The green stems may look gray and bear few hairs. Three leaves form a whorl near each stem's middle. Each leaf has three to five narrow, deeply cut lobes. Sharp teeth line their edges. Leaves turn yellow before the plant rests for summer.

Flowers open from March to May, depending on location. Each plant flowers for about two weeks. Loose clusters sit at the tops of the stems. Each flower has four petals arranged as a cross. White petals may show hints of pink or lavender. Flowers measure about 0.06 feet (0.02 metres) across. Green, narrow siliques follow the flowers. They split four to five weeks after bloom. Each pod holds 10–14 small, flat, brown seeds. Honey bees and bumblebees visit the flowers for nectar. Some early butterflies visit too. Mustard White and West Virginia White caterpillars eat the leaves.

Grow toothwort in partial shade or light filtered through trees. It needs moist, rich soil with good drainage. It accepts clay, loam, and sand with organic matter. It can also withstand some seasonal flooding. Sources place it in USDA zones 3–8. Growth is slow, and rhizomes spread to form colonies. Seed growing is difficult; seedlings take three to four years to flower. Stored seeds soon lose their ability to sprout. Divide the fragile rhizomes while plants are dormant.

Toothwort suits woodland gardens, shaded borders, and naturalized areas. Later-growing perennials can fill the space left by summer dormancy. Sources report no major pest or disease problems. The roots have a sharp, radish-like taste. They can be eaten raw or cooked, including in salads. Leaves are also edible raw or cooked and taste peppery. One source lists no known hazards, rather than proven safety. Historical Iroquois uses included food and treatments for several ailments.