Rumex crispus aka Curled Dock

Rumex crispus is known as curled dock or yellow dock. It belongs to the buckwheat family, Polygonaceae. Its native range spans temperate Eurasia, North Africa, and Macaronesia. It is native to Britain and Ireland. This long-lived perennial grows from a deep taproot. It now grows as a farm weed across much of the world. It occurs in grassland, roadsides, waste ground, and worked soil.

Garden plants reach about 1.6–3.3 feet (0.5–1 metre) tall and wide. Useful Tropical Plants gives a shorter height of 1–2 feet (0.3–0.6 metres). Leaves form a basal rosette about 1 foot (0.3 metres) across. They are simple and pointed, with strongly wavy edges. Larger leaves grow at the base, while smaller ones alternate along stems. The upright green flower stems have ribs and no hairs. The plant sheds its leaves as the season ends.

Small flowers appear in summer on tall, narrow panicles. They have no petals, but their sepals are yellow-green. Wind carries the pollen. The sepals turn brown as they mature. Each flower forms a dry capsule holding one seed. The dark brown seeds have three angles and pointed tips. Brown stems and seed heads can remain through winter. Seeds may stay viable in soil for up to 50 years.

This dock grows in full sun or partial shade. It accepts sand, loam, clay, and chalk across a wide pH range. Moist, well-drained soil suits it, though it also withstands drought. It tolerates brief flooding and some mowing. RHS rates it H7; NC State lists USDA zones 4–8. It provides food for wildlife, including butterfly caterpillars. It can suit wildflower meadows and less-managed garden areas. Yet seeds spread readily, and pieces of root can regrow. Cut stems before seeds form to limit spread. Slugs and aphids may attack it, but disease is seldom a problem.

People use young leaves, peeled stems, and seeds as food. Even young leaves can taste bitter. Oxalic acid makes large servings unsafe, and cooking reduces its level. People with kidney stones, gout, or related conditions need caution. PFAF also warns against use during pregnancy or breastfeeding. The plant can harm both people and pets when eaten in quantity. Reported signs include drooling, tremors, and rare kidney failure in dogs or cats. The roots have a history of use as laxatives and herbal remedies. They also yield dyes, and the plant has served in herbal compost mixes.