Common Teasel

• Common weed found on roadsides and other disturbed areas and recently has begun to invade valuable agricultural lands in Washington.
• Due to the present management practice of mowing old seedheads, seedheads that contain viable seed are being spread along roadways and into various habitats.

• A taprooted, monocarpic plant that grows as a biennial or short-lived perennial that dies after it flowers.
• They develop a stout, fleshy taproot in the rosette stage that can be more than 2 feet long and 1 inch in diameter at the crown.
• Dense flowerheads, up to 4 inches tall, occur individually at the tips of leafless flower stems and opposite side branches.
• Bracts at its base are linear, more or less prickly, curved upward and unequal in length.
• Flowers bloom in 2 rings and are generally pale purple to dark pink.
• Basal leaves are oblanceolate with wavy margins and typically die early in the second season.
• Leaves have spines on the underside of the midvein and smaller spines on bases on the upper leaf surface.
• The stem leaves are opposite and prickly, especially on the lower side of the leaf midvein.
• The second year flower stems grow 0.5-2 meters tall, are striate-angled and increasingly prickly going upward.
• Stems are pithy or hollow and have opposite branching.
• Fruits are dry achenes and about 0.12 to 0.31 inches (3-8 mm) long and typically have 8 pale ribs.

• Grows in garden areas, along creeks, pond edges, roadsides, abandoned fields and other disturbed sites.
• Also grows into agricultural areas, fallow fields, pasture lands and hay meadows.
• It prefers open, sunny habitats and can survive in a range of wet to dry conditions.

• Reproduces from seed.
• A single flowerhead can on average produce around 850 seeds and plants typically produce 1-40 flowerheads.
• Seeds can be dispersed by floating on water, in mud, soil movement, human activities and by animals and birds

• Current control practices in many areas consist of mowing plants and leaving seedheads on the ground.
• Rosettes can be dug up, though it is important to remove as much of the root as possible to prevent resprouting.
• Flowering stalks can be cut from plants where flowering has already initiated and not before or stems will resprout.
• Cut flower stalks should be removed from the area.
• Maintenance of healthy native plant communities will help prevent re-infestation by common teasel. After the control of infestations, seed and plant areas with competitive grasses, forbs and other desirable plant species.

2,4-D amine

• Rate: 1 lb ae/a
• Apply to rosette stage in fall or spring.
• Treating after teasel begins to bolt may not be effective
•  Avoid drift to sensitive crops

2, 4-D amine + dicamba (Banvel, Rifle, or Clarity)

• Rate: 0.75 lb ae/a 2,4-D + 0.125 lb ae/a dicamba
• Apply to rosette stage in fall or spring.
• Treatments made after teasel begins to bolt may not be effective.
• Avoid drift to sensitive crops.

aminocyclopyrachlor + chlorsulfuron (Perspective)

•  Rate: 1.8 to 3.2 oz/a aminocyclopyrachlor + 0.7 to 1.3 oz/a chlorsulfuron (4.5 to 8 oz/a of product)
• Apply to actively growing plants in spring.
• Adjuvants can be used; these include methylated seed oils 0.5 to 1% v/v, nonionic surfactants at 0.25 to 1% v/v, and crop oil concentrates at 1%v/v. Can be applied using an invert emulsion rather than water.
• Even low rates can kill nontarget tree and shrub species, so avoid application within a distance equal to the tree height of the sensitive species. Do not allow spray to drift off target. Can injure several  grass species including bromes, as well as basin wildrye.

Chlorsulfuron (Telar)

• Rate: 0.75 oz ai/a (1 oz/a Telar)
• For best results, apply to actively growing teasel in the rosette stage.
• Constantly agitate while mixing and spraying. Add 0.25% v/v nonionic surfactant to spray mixture. Apply with ground equipment in at least 10 gal/a carrier.
• Registered for use on pasture, range, Conservation Reserve Program (CRP), and non-cropland only. Avoid contact with sensitive crops. Can persist in soil. Do not treat powdery, dry soils or light, sandy soils unless rain is likely soon after treatment. Do not apply to frozen ground.

Diflufenzopyr + Dicamba (Overdrive)

• Rate: 0.26 to 0.35 lb ae/a (6 to 8 oz/a)
• Apply to rosettes.
• Add a surfactant to the spray mix.
• Avoid drift to sensitive crops. Will kill legumes.

Imazapic (Plateau)

• Rate: 0.125 to 0.1888 lb ai/a
• Apply to rosettes.
• Add 1 quart / a methylated seed oil.
• Before using, note crop rotation restrictions.

Metsulfuron (Escort and others)

• Rate: Escort: 0.45 oz ai/a (0.75 oz/a)
• Apply to actively growing plants.
• Using a nonionic or silicone surfactant increases effectiveness. Application sites differ among products; consult labels.
• Apply only to pasture, rangeland and non-crop sites.

Triclopyr + Clopyralid (Redeem R&P)

• Rate: 1.5 pints/a
• Apply when actively growing.
• Add a nonionic surfactant at surfactant manufacturer’s recommended rate. Apply in at at least 10 gal/a water by ground.
• Do not exceed 4 pints/a per year. Avoid drift to desirable vegetation. No label restrictions on over-seeding or reseeding.