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Dyer's Woad

Dyer's woad
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

Common Name: Dyer's Woad

Scientific Name: Isatis tinctoria

Habitat: disturbed areas, roadsides

Provincial Designation: Prohibited Noxious

Prohibited Noxious weeds are plant species that are designated as "prohibited noxious" in the Alberta weed regulation. Prohibited noxious weeds must be destroyed, meaning all growing parts need to be killed or the plant's reproductive mechanisms need to be rendered non-viable.

Origin

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.

Legislated Because

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.

Description

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.