Eagle Lake Field Office

Noxious Weeds of the Eagle Lake Field Office

This plant guide identifies 25 noxious weeds that are known to occur on public land administered by the Bureau of Land Management's Eagle Lake Field Office, located in northeastern California. To view a photograph and more information on an individual plant, click on the plant's common name below.

Bull Thistle

Cirsium vulgare

Canada Thistle

Cirsium arvense

Musk Thistle

Carduus nutans

Plumeless Thistle

Carduus acanthoides

Scotch Thistle

Onopordum acanthium

Wavyleaf Thistle

Cirsium undulatum

Yellowspine Thistle

Cirsium ochrocentrum

Yellow Starthistle

Centaurea solstitialis

Diffuse Knapweed

Centaurea diffusa

Russian Knapweed

Acroptilon repens

Spotted Knapweed

Centaurea maculosa

Squarrose Knapweed

Centaurea sqarrosa

Common Crupina or Bearded Creeper

Crupina vulgaris


Rush Skeletonweed

Chondrilla juncea

Dyer's Woad or Marlahan Mustard

Isatis tinctoria


Hoary Cress

Cardaria draba

Perennial Pepperweed or Tall Whitetop

Lepidium latifolium

Dalmatian Toadflax

Linaria dalmatica


Halogeton glomeratus

Klamathweed or St. Johnswort

Hypericum perforatum

Leafy Spurge

Euphorbia esula

Mediterranean Sage

Salvia aethiopis


Tribulus terrestris

Purple Loosestrife 

Lythrum salicaria


Taeniatherum caput 

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 government agencies mounting an effort to control and prevent noxious weeds, as well as educate the public about how destructive these plants can be.

The information presented here is from the book, Selected Noxious Weeds of Northeastern California, a joint project of the Bureau of Land Management, U.S. Forest Service, Lassen County, Modoc County, Northern Deputy Agricultural Commissioners and Sealers Association, Tuscarora Gas Transmission Company, and the California Department of Food and Agriculture.