Today it is common throughout the western United States and is particularly well adapted to California's climate of winter rainfall and summer drought. Russian thistle is primarily a weed in sites where the soil has been disturbed, such as along highways. It is also prevalent in vacant lots and other noncrop areas, in field and vegetable crops, and in poorly tended landscapes. It is rarely a problem in well-managed gardens or turfgrass. Stems vary from 8 to 36 inches in length and usually have reddish to purplish stripes.
Young plants are suitable for livestock forage and are sometimes grazed.
The single, inconspicuous flowers lack petals and are borne in most leaf axils above a pair of small spine-tipped bracts. The bracts and spiney leaves prevent predation by herbivores as the plant nears maturity. The overall shape of the plant becomes oval to round and may attain a diameter of 18 inches to 6 feet at maturity. After the plant dries, the base of the stem becomes brittle and breaks off at soil level in fall and early winter. These round, thorny plants are capable of dispersing seed for miles as they tumble along in the wind.