Alturas Field Office

Noxious Weeds

 

Wavyleaf  Thistle   (Cirsium undulatum)
Sunflower Family (Asteraceae)

 
Wavyleaf Thistle
Photo courtesy of the California Department of Food and Agriculture
 

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Description:  Perennial from simple taproot, sometimes creeping.Stems erect, branching, 1 to 3-1/2 feet tall, white wooly. Lower leaves 3 to 10 inches long, hairy both sides, with spines 3/16 to 2-3/8 inches long. Upper leaves smaller, toothed, spiny. Flowers one to few, pink to lavender to white. Phyllaries tightly appressed to head, hairy on margins, with a prominent white glandular ridge.

Habitat:  Native from Nebraska to Texas, unintentionally introduced into California. Invades waste areas and rangelands, meadows of sagebrush communities.

Distribution: There is only one known location of wavyleaf thistle in northern California, a site near Loyalton (Sierra County). A yellowspine-wavyleaf thistle hybrid exists west of Termo (Lassen County).

Flowering Period: June to September.