• facebook
  • twitter
  • YouTube
  • RSS feed
  • 651-201-6000
  • 800-967-2474
  • 800-627-3529 TDD
  • PARKING

Loading
NodeFire Save Document
Home > Plants, Pests & Pest Control > Bad Plants > Meadow Knapweed

Meadow Knapweed


Common names: meadow knapweed
Scientific names: Centaurea x moncktonii, C. jacea x nigra, C. pratensis Thuill, and C. debauxii subsp. thuilleri.
Related species: Other knapweeds and hybrids including spotted knapweed, Centaurea stoebe L. ssp. micranthos (Gugler)

Meadow knapweed is native to Europe and is likely a fertile hybrid between black (C. nigra L.) and brown (C. jacea L.) knapweeds. It may have been introduced to western North America for forage, but it is not palatable and has low nutritional. Meadow knapweed escaped cultivation and is proliferating rapidly in the Pacific Northwest. Few meadow knapweed populations have been detected in Minnesota so it would be advantageous to control these populations before they have an opportunity to spread.

Description

Meadow knapweed is a perennial plant that has multiple upright, reddish stems that are 20-40” tall. Single flowers, mostly pink/purple but occasionally white, are at the ends of branches and are approximately ¾” in diameter. Flowering occurs mid-summer until fall followed by the production of white to light brown seeds with short plumes. Leaves are lance shaped and pubescent, occasionally with wavy margins or lobed. Basal leaves grow up to 4” long. Seedlings are tap-rooted and mature plants develop a cluster of roots below the crown.

Spotted knapweed is a similar species that is common in Minnesota. The two knapweed species are easily distinguished by the leaf shape and color. Spotted knapweed leaves are grey-green and are more deeply lobed. Distinguishing meadow knapweed from spotted knapweed.

Meadow knapweed – rosette
Rosette
Meadow knapweed – flower stalk growing from the rosette
Flower stalk growing from
the rosette
Meadow knapweed – seedlings
Seedling
Meadow knapweed – seedhead
Seedhead
Meadow knapweed – mature plants
Mature plants
Meadow knapweed – flower
Flower
Meadow knapweed – flower
Flower
Meadow knapweed – flower
Flower
Meadow knapweed – leaves
Leaves
Meadow knapweed – leaf
Leaf

Habitat

Meadow knapweed prefers sunny and wet conditions such as wet meadows, hayfields, pastures, riparian areas, roadsides, and forest openings.

Means of spread and distribution (view distribution)

Seed is the predominant means of reproduction although meadow knapweed can also be propagated by root crown fragments. Seed can be dispersed by wind, water, vehicles, and with hay. Meadow knapweed occurs in Colorado, Oregon, Idaho, and Washington in the United States and British Columbia, Ontario, and Quebec in Canada. It has very limited distribution in northern Minnesota with infestations reported in St. Louis and Koochiching Counties.

Impact

Meadow knapweed can overtake other plants in pastures, hayfields, meadows, riparian areas, forest margins, and rights-of-way. This can result in reduced forage, wildlife habitat, and species diversity. A similar weed species, spotted knapweed, is abundant and can hybridize with meadow knapweed if the species co-exist. Concerns about a resulting vigorous hybrid add to the rational for meadow knapweed eradication in Minnesota.

Prevention and management

To prevent the introduction of additional meadow knapweed, clean equipment, vehicles, and footwear before transporting to Minnesota from meadow knapweed infested areas.

For all management options, infestation sites will need to be monitored and treated repeatedly until the seedbanks are depleted.

  • A combination of hand-pulling and digging is an option for small infestations. Seedlings are tap-rooted and can be hand-pulled. However, the root clusters of mature plants are near impossible to hand-pull and must be dug and the entire root cluster removed to prevent regeneration. Plants with flowers and/or seedheads should be bagged and disposed.
  • Herbicides are a very effective management tool for meadow knapweed. For specific herbicide recommendations, contact your University of Minnesota Regional Extension Educator.
  • Mowing does not control meadow knapweed and the mower may spread seed.
  • Biological control was developed for some other knapweed species, but is not an effective control option for meadow knapweed.

    Legal status

    Meadow knapweed is not regulated in Minnesota, but will be evaluated by the Minnesota Noxious Weed Advisory Committee.

    More information

    Additional images, fact sheets, and best management practices at: