Photo credit: Steve Dewey, Utah State University, Retrieved from Bugwood.org (Image Number: 1459931), used under CC BY 3.0 US, modified from the original
Dyer's woad is native to southeast Russia and central Asia. It was introduced to eastern North America in the 17th century as a medicinal herb and source of indigo dye.
A single Dyer's woad plant can produce as many as 10,000 seeds per year. This plant can invade crop fields and grassland and out-compete native species. It reduces yields of crops and forage.
This weed has small yellow flowers with four petals arranged in a cross-shape.
Basal leaves have long stalks but stem leaves are sessile and clasp the stem. All leaves are blue-green in colour and have a distinctive cream-colored midrib.
The plant grows up to 120 cm tall with a heavily branched upper portion.