A native of eastern Europe, this annual is also known as tumbleweed. The plants grow 1/2 foot to 3 feet tall, with reddish, spreading or erect stems. The leaves on young plants are fleshy and cylindrical. As the leaves mature, they drop and stiff, narrow leaves ending in a spike appear. From July to October, greenish flowers bloom and produce thousands of seeds. In early fall, the plants break off at the soil line and tumble about, distributing the seeds. Russian thistle prefers areas with dry soil along roadways and in fields and unmaintained areas.
To prevent seeds from germinating around trees and shrubs and in flowerbeds, use a preemergent weed killer. Apply to the soil in the spring about the time of the last frost (2 weeks after forsythia blooms).