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Foxtail Grass

Foxtail grass is a common name used for several grasses with dense, brush-like seed heads that resemble a fox’s tail.

By Ethan Anderson| Reviewed by Olivia Bennett, Standards & Fact-Checking Lead| Updated July 26, 2026|2 min read| Fact-checked

Foxtail grass is a common name used for several grasses with dense, brush-like seed heads that resemble a fox’s tail. The term most often refers to species in the genera Setaria and Alopecurus, and it is not a single formal botanical group. Some foxtails are weedy and invasive, and their barbed seeds can irritate or injure animals and people.

Naming and classification

Foxtail grass is a collective common name applied to multiple grasses, especially species in Setaria and Alopecurus. Because the term is informal, different regions may use it for different plants.

Identification

Foxtails are recognized by their dense, cylindrical or brush-like seed heads and their bristly seed structures. The seed heads resemble a fox’s tail, which is the basis of the name.

Ecology and spread

Many foxtail species are annual grasses that emerge in late spring and summer, grow in clumps, and spread through prolific seed production. They are common in disturbed habitats, turf, pasture, and crop fields.

Effects on animals and agriculture

The sharp awns on foxtail seeds can irritate skin and may lodge in animals’ ears, noses, mouths, or paws. In agriculture, foxtails can compete with crops and reduce forage quality and yield.

Key facts

  • Foxtail grass is an informal common name, not one official species or genus.
  • Many foxtail grasses are summer annual weeds that reproduce only by seed.
  • Barbed seed awns can become embedded in animals’ skin, ears, noses, or throats.
  • Some foxtail species are considered invasive or noxious weeds in parts of North America.
  • Foxtail grasses are relevant to Canadian agriculture and pasture management.
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Canadian context

Foxtail grasses are relevant to Canadian agriculture, turf management, and pasture management because some species behave as troublesome weeds and can reduce forage quality. Canadian readers may encounter them in disturbed ground, fields, and grasslands, and similar barbed-seed issues are noted for livestock and pets.[15][18]

Frequently asked questions

Is foxtail grass one plant species?
No. It is a common name used for several grass species, especially in the genera Setaria and Alopecurus.
Why is it called foxtail grass?
The seed heads are dense and bristly, resembling the tail of a fox.
Are foxtail grasses annual or perennial?
It depends on the species. Many weedy foxtails are annuals, while some Alopecurus species are perennial.
Why are foxtails a concern for pets?
Their barbed seeds can attach to fur and may lodge in the ears, nose, skin, or throat, causing irritation or injury.
Where do foxtail grasses grow?
They are found in lawns, fields, roadsides, pastures, crops, and other disturbed areas, especially in temperate regions.
Are foxtails invasive?
Some species are considered invasive or noxious weeds in parts of North America, but this depends on the species and location.

References

  1. King County Noxious Weed Control Programhttps://kingcountyweeds.com/2026/01/14/foxtail-grasses/
    Supports: Foxtail is a common name for several grasses; not an official botanical grouping; barbed seeds and invasive nature.
  2. Purdue University Agriculturehttps://ag.purdue.edu/department/btny/ppdl/potw-dept-folder/2022/foxtails.html
    Supports: Foxtails are summer annual grasses; common species include giant, yellow, and green foxtail.
  3. Washington State Universityhttps://hortsense.cahnrs.wsu.edu/fact-sheet/weeds-foxtail-setaria-spp/
    Supports: Scientific name Setaria spp.; family Poaceae; annual grass.
  4. University of Maryland Extensionhttps://extension.umd.edu/resource/know-your-foxtails-fs-2023-0658
    Supports: Foxtails are grasses in the genus Setaria; bristled seedheads; common species.
  5. Encyclopaedia Britannicahttps://www.britannica.com/plant/foxtail
    Supports: Foxtail applies to grasses in Alopecurus and Setaria; bristled seed clusters; animal injury potential.
  6. University of Nevada, Reno Extensionhttps://extension.unr.edu/publication.aspx?PubID=7083
    Supports: Foxtails as invasive grasses; effects on forage quality and livestock injuries.