Canada thistle (Cirsium arvense) is a Perennial that infests disturbed sites, such as roadsides and open fields, as well as hillsides, open forests, pastures, rangelands, crop fields, stream banks, and other riparian areas.

Its tendency to prefer moist soils makes this plant especially problematic in Riparian areas and moist soil meadows in Taos County.

Quick facts

Also known as: corn thistle, creeping thistle.

Stems/leaves: Stems (1-4 ft. tall) are nearly glabrous, branched near the top, green to brown; leaves (2-8 in. long) are green, oblong to lanceolate; leaf margins are wavy, lobed, or toothed with prickly spines (0.1–0.25 in. long).

Flowers: Produces flower heads in clusters; individual heads (0.5 in. in diameter, 0.5-1.5 in. long) are oval- to bell-shaped, with dark-tipped bracts below flowers; flowers are pink, purple, or white

Roots: Extensive creeping perennial root system.

Reproduction: Creeping perennial roots and seed reproduction

  • Management do’s and don’ts
  • Early detection and eradication are the most effective control methods.
  • Repeated cultivation, mowing (before seed production), or hand removal is effective.Herbicides are effective.
  • Maintaining a healthy plant community can prevent establishment and slow spread.

For more information on Canada thistle and other invasives, visit the Taos Soil and Water Conservation District website: tswcd.org/noxious-weeds.

Please join the following partners in our battle against noxious and invasive weeds in the place we call home:

Taos Soil and Water Conservation District, USDA Carson National Forest, USDI Bureau of Land Management (Taos Field Office), New Mexico Department of Agriculture, New Mexico State University Agricultural Extension Office, New Mexico Department of Transportation, New Mexico Division of Forestry, Southern Methodist University (Taos Campus), Taos County, Town of Taos, Amigos Bravos, Taos Land Trust, Rocky Mountain Youth Corps, New Mexico Native Plant Society (Taos Chapter), Sunset Park Inc., and Rio Grande Ace Hardware.

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