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Pacific Northwest Research Station
Blue Mountains National Resources Institute

Forestry and Range Sciences Laboratory
1401 Gekeler Lane
La Grande, OR 97850

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BMNRI Home > Publications > Weeds > Dyers Woad


Publications: Noxious Weeds

Explosion in Slow Motion: A talk by Jerry Asher about noxious weeds in the Blue Mountains


Click on a weed to learn about how to find it and kill it!


Common Crupina
Diffuse Knapweed
Russian Knapweed
Spotted Knapweed
Purple Loosestrife
Perennial Pepperweed
Puncturevine
Tansy Ragwort
Medusahead Rye
Rush Skeletonweed
Yellow Starthistle
Canada Thistle
Musk Thistle
Scotch Thistle
Dalmatian Toadflax
Mediterranean Sage
St. Johnswort
Leafy Spurge
Whitetop
Dyers Woad

Wanted: DEAD!

Dyers Woad

 

Stems: 1 to 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, four 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 in 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.


Control: Prevent new infestations.

  • Biological: Sheep have been relatively ineffective. 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 you 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.

Report all sightings to your local Weed Board

US Forest Service - Pacific Northwest Research Station, Blue Mountains National Resources Institute
Last Modified: Monday, 16 December 2013 at 14:18:43 CST


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