Rubia tinctorum aka Dyer's Madder

Rubia tinctorum is known as madder or dyer's madder. This evergreen climbing perennial belongs to the coffee family, Rubiaceae. Its native range runs from southeast Europe to Xinjiang and the western Himalaya. Kew also records it on Mount Fansipan in Vietnam. It grows in temperate regions. Wild plants occur in hedges, neglected ground, and rubble. People have long grown madder for the red dye in its roots.

In gardens, madder reaches about 1.5–3.3 feet [0.45–1 metre] tall and wide. It grows at a medium rate and spreads among nearby plants. Its green stems have four sides and small, curved hooks. Hooks on the leaves also help it climb through nearby growth. A trellis can support the stems. The narrow, simple leaves have smooth edges. They sit in whorls of four to seven around each stem. Leaves can reach about 0.33 feet [0.1 metre] long.

Small yellow flowers form dense clusters during summer. North Carolina State records bloom from June through August. The RHS gives the shorter period of July and August. Each star-shaped flower has four or five petals. The berries start green, then turn red as they ripen. Sources describe the final fruit colour as purple or black. Both the flowers and berries measure less than 0.08 feet [0.025 metre] across.

Grow madder in full sun, though it also tolerates part shade. It suits fertile sand or loam with good drainage. It accepts acid, neutral, and alkaline soil. Sources describe suitable soil moisture as dry to moist. The RHS rates it H6; North Carolina State lists USDA zones 5–9. Plants take two to five years to reach full size. Seeds may sprout slowly, while division offers another way to raise plants. The RHS advises cutting stems back in autumn.

Madder suits coastal sites, cottage gardens, and wildflower or wildlife plantings. Small groups can fit these settings, but its spread needs watching. Side shoots run just beneath the soil and send up new growth. These can make it troublesome, despite its low care needs. Sources report few pest or disease problems. Its root dye has coloured leather, wool, cotton, and silk. The rough leaves and stems have also served to polish metal. Plants For A Future records no food uses. It warns of possible cancer risks, including liver and kidney cancers. Despite past medicinal uses, that source advises against taking madder as herbal medicine.