welcome to the

     Douglas county conservation district

serving landowners in Douglas County, Colorado for over 50 years

                                Box 688, 7519 E. Hwy 86, Franktown, CO 80116, 303-688-3042 ext. 100

Home
DISTRICT INFO
EDUCATION / INFO
EVENTS
FINANCIAL ASSIST
NOXIOUS WEEDS
PRODUCTS
SCHOLARSHIPS
SEEDLING TREES
SERVICES
WATERSHED DAMS

Canada Thistle
Cirsium arvense

Stems are 1 to 4' tall, ridged, branching above.  Leaves are alternate, oblong or lance-shaped, divided into spiny-topped irregular lobes.  Flowers are unisexual, on separate plants; flowers purple (occasionally white) in heads 1/2 to 3/4 inch in diameter.  Fruits are about 1/8 inch long, somewhat flattened, brownish, with a tuft of hairs at the top.

Differs from other species of the true thistle in that there are male and female flower heads, and these are on separate plants.  By asexual reproduction, it is possible that a colony of male plants would produce no fruits, but still maintain itself.  Flowering occurs during July and August.