Reseda Species, Dyer's Rocket, Dyer's Broom, European Mignonette, Weld, Yellow Wee

I've seen this growing on pure chalk rubble in an old quarry, it can clearly tolerate very poor soil as well as strongly alkaline conditions.

This is the oldest yellow dye plant in the world. It is again gaining popularity as an organic dye.

Biennial to 5', stems hollow, little branched; leaves entire, basal leaves narrowly oblanceolate, to 3" long, stem leaves narrowly oblong...Read More; racemes dense; sepals and petals usually 4, stamens 20-25; capsule 3-lobed nearly to middle, to 1/4" long.

A frequent biennial weed of mineral soils on rubbish dumps and disturbed ground; especially abundant in old limestone quarries. The plant is tall with a long spike of small yellow flowers and with narrow wavy-edged leaves.

Formerly cultivated as a source of a deep yellow dye; occasionally planted in collections of economic plants.

Naturalized in the United States. The root of this plant is conical, and resembles in taste and odor the garden radish. It contains allyl-sulphocyanate a volatile oil of mustard. A persistent bitter taste is imparted by the herb. It contains silky yellow crystals of a coloring body, luteolin. It is feebly bitter and somewhat astringent. It is quite soluble in alcohol, and less so in ether and water. Fused with caustic potash it yields protocatechuic acid, phloroglucin, and carbon dioxide. It is now used only in dyeing; formerly it was employed to increase the renal and cutaneous secretions.