Dyer's Woad

(a.k.a. Isatis tinctoria)

Dyer's Woad is an herb associated with the mustard family. Its origins date back over 2000 years. In Europe, this plant has been cultivated as a source of blue dye and for medicinal properties since the 13th century. Within the last century it has become a serious problem on rangelands and in cropland of the United States. This plant, as found in Utah, is a winter annual, biennial, or a short lived perennial.

Distinguishing Features

  • Stems: 1-3 feet tall, simple below, branched above.
  • Leaves: Basal leaves form a rosette 8 inches long, stalked, widest near apex, bearing soft fine hairs; leaves of the stem shorter, alternate, lanceolate, sessile, and with a pair of short basal lobes clasping the stem, mostly entire and without hair.
  • Flowers: Small, 4 sepals and petals, yellow, about 1/4-inch across. Borne in dense clusters on the stem tip. Flowering period is from April to July.
  • Seeds: Seeds are contained 3/4-inch tear-shaped, purplish-brown fruits
  • Dyer's woad can be either perennial or biennial. It is cultivated for blue dye. It thrives in light sandy soil and forms dense stands on grazing and marginal farm lands. It spreads by seed into dry areas.

Join the Invasive Weed Patrol

  • Control: Prevent new infestations.
  • Biological: Sheep and a recently discovered pathogen may have application as a host-specific control agent.
  • Chemical: Most effective before the plant sends up a stem. After the flower stem appears, herbicides have little effect. Consult your local weed board for current regulations and other information.
  • Mechanical: Hand pull or dig out individual plants. Cultivate early in the spring to prevent it from getting a start. Destroy new seedlings in the fall.

Your Reward

A cleaner, healthier environment and the satisfaction that you have helped make the difference!

Photo of a dyer's woad flower head





https://www.fs.usda.gov/detail/ashley/learning/nature-science/?cid=stelprdb5279716