Foxtail…Harmful Pasture Weed

By: Eddie Ayers, County Extension Agent

You might be asking yourself “just what is a foxtail?” Foxtail is an invasive weed in pastures and
hayfields that produces a seedhead with hurtful sharp awns. The weed gets its name because the seed head
looks like a fox’s tail. Livestock likes to feed on the plant when it’s young because it’s full of protein and
very palatable. However, mature foxtail plants are less palatable, have poor digestibility, and are full of
sharp seeds. Hay quality can be greatly impacted by the presence of foxtail seedheads. Foxtail
populations often out-compete hayfield grasses for light, water, and nutrients required to optimize yields.
The identification of the foxtail species is critical for planning control programs in pastures and hayfields.

Annual foxtail species found in Georgia include giant foxtails (Setaria faberi), green foxtails (S. viridis),
and yellow foxtails (S. pumila). These species establish from seed in spring, exhibit vegetative growth in
summer, and complete their lifecycles in autumn. Annual foxtails have a clumped growth habit with
fibrous root systems. Giant foxtail seedheads are cylindrical panicles that often droop upon plant maturity.
The seedheads of green and yellow foxtail have a linear, erect growth pattern.

Knot root foxtail (Setaria parviflora) is a warm-season perennial with short rhizomes. This species may
rapidly infest grazed pastures when forage competition is limited. The seedhead is a cylindrical panicle,
similar to other foxtails, but with a more compacted size than the annual species. Knot root foxtail may
germinate from seed or from rhizomes in spring. The rhizomatous growth contributes to the invasiveness
of the species and persistence in pastures and hayfields.

Promoting competitive growth of pasture species with foxtail populations is critical for long-term
successful control. Annual foxtails begin to germinate in early spring when soil temperatures reach
approximately 60 degrees Fahrenheit. The lifecycle of these species is predictable, and therefore, growers
can modify management programs to reduce spring establishment. For example, nitrogen fertilization
should be reduced during peak germination in areas with a history of foxtail populations. Excessive
nitrogen use in summer will also encourage seed production, dispersal, and survival. Grazing may
suppress foxtail populations and minimize competition with pasture species. Mechanical suppression
through mowing can inhibit foxtail growth and limit the spread of seed in pastures.

Actively growing foxtail plants will regenerate seedheads within about two weeks of mowing. Therefore,
regular mowing may be needed for effective suppression in grazed pastures. Mowing does not eradicate
foxtails, and seedhead suppression may only be temporary. Practices that disturb the soil, such as
aeration, sub-soiling, or tilling operations, should be conducted when pasture grasses are actively
growing. Voids left in fields with exposed soil may permit foxtail invasion. Timing these operations
during favorable periods for quick recovery promotes competition with foxtails. In tall fescue and cool-
season forages, growers should reseed thinned areas to promote competition with foxtails establishing in
spring.

Foxtail can be controlled with herbicides. There are pre-emergent and post-emergent ones that are labeled
to control foxtail species. Please read the label to choose the right herbicide to use in your forage and
always follow the instructions when using herbicides. For more information contact me in the Gilmer
County UGA Extension office or visit:

https://secure.caes.uga.edu/extension/publications/files/pdf/B%201464_1.PDF to read the entire bulletin
in the publications section of our website.

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