Reseda luteola aka Weld

Reseda luteola, known as weld or dyer’s rocket, belongs to the Resedaceae family. Its native range spans Macaronesia, North Africa, and Europe. It extends east to Central Asia and Pakistan. It has naturalized in the Americas and Australia. Australia classes it as invasive. Weld grows on disturbed ground, farmland, and walls, often on lime-rich soils.

This upright plant usually lives for two years. It forms a leaf rosette in its first year. It flowers, sets fruit, and dies in its second year. Some plants complete this cycle in one year. Garden plants reach about 2–5 feet [0.6–1.5 metres] tall. They spread to about 1.6 feet [0.5 metres]. The deep green leaves are lance-shaped, with wavy edges. They grow alternately and have a leathery feel. Some foliage may remain through winter.

Tall, narrow flower spikes rise above the leaves. Sources place flowering in spring or summer. The tiny flowers range from greenish to yellow. Each has three or four petals with finger-like lobes. Many stamens crowd the centre of each flower. The blooms have scent, though each flower makes little show. Groups of plants give a stronger display. Brown capsules follow, each under one inch [0.025 metres] across. Weld attracts pollinators and hosts cabbage white butterflies.

Grow weld in full sun or light shade. Choose soil that drains well, preferably neutral or alkaline. It grows in sand, loam, chalk, and stony ground. Poor, dry soil suits it, but heavy clay does not. It needs no added fertilizer. RHS rates it H6; PFAF lists USDA zones 5–9. Sow seeds where the plants will grow. Leave them uncovered, since light helps them germinate. Autumn sowing can produce flowers the next summer. Young plants may need winter cover in colder areas. Avoid disturbing their roots when moving them.

Weld suits meadows, gravel beds, cottage gardens, and sunny banks. It needs little care and has few reported pest or disease problems. Yet it can seed freely and become weedy. Remove spent flowers when seeds are not needed. Its leaves and stems yield yellow dye. PFAF also identifies the seeds as a rich dye source. Seed oil has served as lamp fuel. PFAF gives it no food-use rating and reports no known hazards. It also records mild narcotic uses. These records do not establish that weld is safe to eat.