Dyer’s woad ranges from 1 to 4 feet tall with a deep taproot. The plant acts as a winter annual, biennial, or short-lived perennial. The basal rosette produces stalked, bluish-green leaves covered with fine hair. Leaves have a white mid-rib on the upper surface of the leaf. The flowers are numerous, yellow, and very small. Flowers are clustered on the upper portion of multi-branched stems, which typically occurs in April to early June. Fruit or seed pods are winged, slightly pear-shaped, and change from light green to a shiny purplish-black color as they mature. The seeds contained in the fruit are cylinder-shaped and brownish-yellow. The seeds usually form in June and July.