Early leaves are linear and fleshy, much like pine needles, but as the plant matures, later leaves are short and spiney and much more capable of conserving moisture. Russian thistle normally matures in late summer. An abscission layer forms in the stem near the soil surface that allows the shoot to break off from the taproot in fall and early winter. A large Russian thistle plant may produce more than 200,000 seed. In spring, months after their dissemination, it is possible to trace the paths of tumbleweeds across plowed fields by the green trails of germinating Russian thistle seedlings.
Russian thistle can tolerate alkaline soil conditions.
It is very competitive when moisture is a limiting factor to the growth of other vegetation, when soils are disturbed, or when competing vegetation is suppressed by overgrazing or poor crop establishment. If moisture is not limiting, Russian thistle is less competitive with other species. Seedlings of Russian thistle are suppressed when other plants become established first and shade out the sunlight. There have been numerous attempts through the years to import biological control agents, but none have been successful. Normally the best place to look for a biological control agent is the native habitat of the species.