Woad , is a flowering plant in the Brassicaceae family. Woad is also the name of a blue dye produced from the leaves of the plant. Woad (Isatis tinctoria) is an erect biennial that grows to between 1-3 feet, sometimes up to 4 feet in height. Its leaves are bluish green overlaid with a powdery white fluff. The leaves are narrow and lightly serrated to wavy. The plant blossoms with small yellow flowers in the spring of its second year of growth and develops into blue or black fruit.
The plant was cultivated for centuries as a medicinal and source of natural blue dye.