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Taxon  Report  
Centaurea jacea  L.  ssp. pratensis  (W.D.J. Koch) ?elak.
Meadow knapweed
Centaurea jacea ssp. pratensis is an annual or perennial herb that is not native to California.
Cal-IPC rating: moderate
Siskiyou Del Norte Modoc Humboldt Shasta Lassen Trinity Plumas Tehama Butte Mendocino Glenn Sierra Yuba Lake Nevada Colusa Placer Sutter El Dorado Yolo Alpine Napa Sonoma Sacramento Mono Amador Solano Calaveras Tuolumne San Joaquin Marin Contra Costa Alameda Santa Cruz Mariposa Madera San Francisco San Mateo Merced Fresno Stanislaus Santa Clara Inyo San Benito Tulare Kings Monterey San Bernardino San Luis Obispo Kern Santa Barbara Ventura Los Angeles Riverside Orange San Diego Imperial
Observation Search
~194 records in California
redone or more occurrences
within a 7.5-minute quadrangle

Bloom Period
Parent: Centaurea jacea
Genus: Centaurea
Family: Asteraceae  
Category: angiosperm  
PLANTS group:Dicot
Jepson eFlora section: eudicot

Wetlands: Occurs usually in non wetlands, occasionally in wetlands
Name Status:
Accepted by JEF

Alternate Names:
JEFCentaurea Xmoncktonii
JEFCentaurea Xpratensis
ICPNCentaurea debeauxii
CalfloraCentaurea jacea nothosubsp. pratensis
Information about  Centaurea jacea ssp. pratensis from other sources

[Cal-IPC] Invasive: Centaurea jacea ssp. pratensis (=Centaurea debeauxii or C. jacea x C. nigra or C. x pratensis) (meadow knapweed) is a bushy perennial (family Asteraceae) found in a small number of disturbed areas in Siskiyou, Del Norte, and Humboldt Counties in northwestern California. Meadow knapweed reproduces by seed and via shoots from the parent plant, and is known to resprout from root fragments after cultivation. The seeds can also be spread by irrigation systems and vehicles. Meadow knapweed spreads very rapidly and is listed as a noxious weed in several western states as well as California. Cal-IPC Rating: Moderate Alert (contributed by Mary Ann Machi)

[www.mda.state.mn.us] European native, Description: 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 value. Meadow knapweed escaped cultivation and is proliferating rapidly in the Pacific Northwest.

Description: Meadow knapweed is a perennial plant that has multiple upright, reddish stems with vertical ridges that are 20 to 40" tall. Single flowers, mostly pink/purple but occasionally white, are at the ends of branches and are approximately " 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 4 to 9" long. Seedlings are tap-rooted and mature plants develop a cluster of roots below the crown. Flower buds and young leaves have a cobwebby appearance. (contributed by Mary Ann Machi)

Suggested Citation
Calflora: Information on California plants for education, research and conservation, with data contributed by public and private institutions and individuals. [web application]. 2024. Berkeley, California: The Calflora Database [a non-profit organization]. Available: https://www.calflora.org/   (Accessed: 04/13/2024).