Leaves were an important blue dye in the Middle Ages. Caesar recorded in 55 B.C. that the Picts of Britain dyed their skin with woad.
Source of plant
Cornell Botanic Gardens
Biennial, reaching 3' in height, glabrous above. Leaves oblong to lanceolate, to 4" long, entire or toothed, stem leaves clasping or auricled. Flowers yellow in terminal panicles.
USDA Hardiness Zone
other ethnobotanical uses