An annual weed, extremely prostrate and mat-forming, spreading out in a circle to 10 feet in diameter. Very shallow but tough taproot. Seeds germinate in early spring, but can remain viable in the soil for 5 years. Plants mature throughout the summer, and may produce copious amounts of seeds. Seeds are spiked and very hard, creating havoc with bicycle tires that easily are punctured.
The spiny seeds are commonly carried in vehicle tires, spreading the weed quickly. Seeds may remain viable in soil for 5 years, increasing difficulty of control. The seeds tangle in sheep wool, making it damaging, they are a problem in hay, and may injure livestock that consume them. Weeds grow in most soil conditions, from cultivated fields to hard packed roadsides, trails and paths as well as gardens. Individual plants may be physically removed prior to production of the seeds. Seeds may remain viable in the soil for several years before they germinate.