Introduced from Asia, and found in California and Hawaii as an occasional weed in waste areas and along roadsides.
An annual weed that reproduces from seeds. Very similar to Barnyard grass in its appearance and biology. Seeds have a long spine attached to them that easily attaches to passing clothing or animals, helping the spread of the weed.
Mature plants grow to over 3 feet in height, with several long, weak stems growing erect or falling over as the plant grows. Leaves tend to be shorter than the stems and seedheads, and there is no ligule at the collar where the leaf parts with the stem. Flowering heads are very similar to barnyard grass but have very long, undulating spines on each seed. Many seed heads are produced at the upper end of the stem, each from 1 to 2 inches in length and with several dozen seeds on each head.
Characteristicts Important to Control:
A pre-emergent herbicide can be effective in reducing infestations from seed. Established plants can be killed with a contact or systemic product applied prior to maturation of the seeds.