The Dirt | Weed of the Month April 2026 | Bristly dogtail (Cynosurus echinatus)
Our April Weed of the Month is Bristly dogtail (Cynosurus echinatus). One of many invasive annual grasses in Oregon, bristly dogtail is a tufted annual grass that is known for its noticeably one-sided inflorescence (flowering head). It can grow up to 6 feet tall (but is usually shorter), has a wrapped leaf sheath partially enclosing a prominent ligule, and has smooth, non-hairy nodes. It is often found in dry, open areas such as roadsides, dry grasslands, and upland prairies. It is common throughout the Willamette Valley.
Bristly dogtail is an aggressive noxious weed. It is known to dominate the ecosystems listed above and displace ecologically-important plants if left unmanaged. This species a prolific seed producer and can expand its population quickly throughout the course of a year. Therefore, it is recommended to manage this grass early and often. For small to medium infestations, try pulling or digging out the tufts. Mowing and solarizing are also effective. For large infestations, it is recommended to apply a grass-specific herbicide. Consult with a local herbicide applicator for specific chemical recommendations.
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