Russian thistle is an annual weed, reproducing by seeds.
The stems are up to 1.2 m tall, red striped, and spread as much or more horizontally as vertically. The leaves are alternate, long, 2-5 cm, narrow, dark green, and fleshy. The later leaves are shorter, broader, and are tipped with stiff spines. Two spiny-tipped bracts accompany each flower. Russian thistle can produce up to 200,000 seeds per plant.