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California Poppies Headwaters Forest Reserve Kayaker enjoying the California Coastal National Monument Headwaters Forest Reserve King Range National Conservation Area
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Arcata Field Office

Invasive Noxious Weeds

This plant guide identifies 22 noxious weeds that are known to occur on public land administered by the Bureau of Land Management's Arcata Field Office, located in northwestern California.  To view more information on an individual plant, click on the plant's photograph or common name below.

Agencies Will Loan Tools to Defeat Scotch and French Broom

European Beachgrass

 European Beach Grass growing on ocean sand dunesEuropean Beach Grass growing on ocean dunes

Ammophila arenaria

Yellow Bush Lupine

Yellow Bush Lupine flowers

Lupinus arboreus

Hottentot Fig



Carpobrotus edulis

Bermuda Buttercup flowers

Sea Fig

Photo of Sea Fig

Carpobrotus chilensis

Medusahead Grass

Photo of Medusahead Grass

Taeniatherium caput-

Yellow Starthistle

Photo of Yellow Starthistle

Centaurea solstitalis




Andean Pampas Grass

Andean Pampas Grass

Cortaderia jubata

Ripgut Brome


Bromus diandrus

Canada Thistle

Photo of Canada Thistle

Cirsium arvense

Bull Thistle

Photo of Bull Thistle

Cirsium vulgare

 French Broom flowers
Genista monspessulana


Photo of Klamathweed
Hypericum perforatum

Himalayan Blackberry


Rubus discolor

Gopher Weed

Gopher Weed

Euphorbia lathyris 

Japanese Knotweed

Japanese Knotweed 

Polygonum cuspidatum


Periwinkle flowers 

Vinca major

Tansy Ragwort

Tansy Ragwort 
Senecio jacobeae

English Ivy

Tree covered with English Ivy

Hedera helix






Scotch Broom

Scotch Broom Flowers


Cytisus scoparius


Noxious weeds are non-native plants introduced to North America from Europe and Asia. These plants have spread at an alarming rate because, unlike native species, there are no native insects, fungi, or diseases to control their growth and spread in this country. What began as a handful of plants introduced in the 19th century, now number in the hundreds of millions. Noxious weeds destroy wildlife habitat and forage, threaten endangered species and native plants, increase erosion and groundwater loss, and prevent recreational activities.

Estimates indicate that noxious weeds are spreading at rate of 4,600 acres per day on federal lands alone in the western United States.  They have invaded approximately 17 million acres of public rangelands in the West -- more than quadrupling their range from 1985 to 1995. In northern California, yellow starthistle expanded its range from 1 million acres in 1981 to 10 million acres in 1997.

The Bureau of Land Management is just one of many governement agencies mounting an effort to control and prevent noxious weeds, as well as educate the public about how destructive these plants can be.

Much of the information presented in these write-ups was taken from 1) the book Invasive Plants of California's Wildlands Edited by Carla Bossard, John Randall, and Marc Hoshovky. University of California Press, 2000; and 2) the Nature Conservancy Global Invasive Species Team website: