Foxtails of the genus Setaria are summer annual grasses. Yellow, Setaria pumila, and green, S. viridis, foxtails consist of a complex of many biotypes. Yellow foxtail is found in the central-western region, Central Valley, South Coast, Mojave Desert, southwestern Great Basin east of the Sierra Nevada, and low elevations of the eastern Klamath Ranges, Cascade Range, and Sierra Nevada, up to about 3900 feet (1200 m). Green foxtail is found throughout low-lying and foothill areas of California, except in the Mojave Desert and Great Basin, to about 1000 feet (300 m). Giant foxtail, S. faberi, a species uncommon in California, is sometimes found in southeastern Sacramento Valley and the adjacent Sierra Nevada foothills, up to an elevation of 328 feet (100 m). Foxtails inhabit agricultural land and other disturbed areas. Yellow foxtail also inhabits turf. All grow in moist or dry soil and tolerate a broad range of environmental conditions.
Habitat
Roadsides, ditch banks, fields, pastures, cropland, orchards, vineyards, gardens, and other disturbed sites.
Seedling
First leaves are usually parallel to the ground.
Mature Plant
Foxtails grow in loose clumps or sometimes singly. Stems are erect or bent at the base, but overall ascend upward. Mature foxtails range in height from 1 to 3 feet (30–90 cm) and branch at the base. Leaf blades are 4 to 15 inches (10–37.5 cm) long, and most have a spiral twist.
Collar Region
The ligule of yellow foxtail consists of a fringe of short hairs. Auricles are lacking. There are no hairs on the leaf sheath margin below the collar as in green foxtail. If the leaf sheath of green foxtail is pulled away from the stem, you can see fine hairs on the leaf sheath below the collar region and the leaf blades are flat and lack hairs. Giant foxtail sheaths are cylindrical or slightly flattened, with hairs at the margins.
Flowers
Bloom times for these species are:
- Giant foxtail: June through November
- Green foxtail: May through November
- Yellow foxtail: June through December
Flower heads are spikelike, bristly, and densely packed with flowers (florets). Giant foxtail flower heads range from about 3 to 7 inches (7–18 cm) long; yellow foxtail flower heads 7/10 to 3 inches (2–8 cm) long; and green foxtail flowerheads 7/10 to 6 inches (2–15 cm) long.
Reproduction
Reproduces by seed.
Related or Similar Plants
- Yellow foxtail, Setaria pumila
- Green foxtail, Setaria viridis
More Information
- Grass identification illustration
- Calflora distribution map: Giant foxtail, Setaria faberi
- Calflora distribution map: Green foxtail, Setaria viridis
- Calflora distribution map: Yellow foxtail, Setaria pumila
- For agriculture: UC IPM Pest Management Guidelines
- Identify a weed
- List of all weeds
- Key to weeds in turf
