Foxtail is a collective name for several common grass species, primarily belonging to the Setaria and Hordeum genera. Recognized by their distinctive brush-like seed heads, these plants are widespread annual or perennial weeds found across the globe. Understanding the specific environments where these grasses flourish is essential for effectively managing their spread.
Identifying Foxtail Varieties
The term “foxtail” refers to two major groups of grasses. The first group includes Setaria species, such as Giant Foxtail (Setaria faberi), Green Foxtail (Setaria viridis), and Yellow Foxtail (Setaria pumila). These are primarily summer annual agricultural and lawn weeds that grow in loose clumps and complete their life cycle within a single growing season, reproducing solely by seed.
The appearance of their seed heads helps distinguish them. Giant Foxtail features a longer seed head that often droops as it matures, while Yellow Foxtail has a more erect head surrounded by numerous yellow bristles. Green Foxtail is generally shorter and more variable, and its leaves are hairless, unlike the short hairs found on Giant Foxtail leaves.
The second group includes species like Foxtail Barley (Hordeum jubatum), a short-lived cool-season perennial. This variety is problematic because its seed heads possess barbed awns that easily lodge in the fur, eyes, and noses of animals. Foxtail Barley’s bristly seed spike breaks apart easily when mature, facilitating its spread and acting as a mechanical irritant to livestock and pets.
Global and Regional Distribution
Many foxtail species are classified as cosmopolitan weeds, found in nearly all suitable temperate regions across the world. Green Foxtail, for instance, is native to Europe but has successfully invaded and adapted to local conditions in most temperate countries in both the Northern and Southern hemispheres. They often outcompete native flora in disturbed areas.
In North America, Setaria species are widespread and considered some of the most troublesome weeds in agricultural systems. They are concentrated throughout the major agricultural belts of the United States and Canada, where they were introduced and quickly established a presence. Foxtail Barley, which is native to North America, has also become weedy in many areas, particularly in western states.
Preferred Growing Environments
Foxtail grasses are highly opportunistic, thriving in environments with little competition from established plants. A primary factor in their establishment is disturbed soil, including agricultural fields, construction sites, and roadside verges. Setaria seeds germinate readily in these conditions, emerging from shallow soil depths.
These grasses tolerate a wide range of soil textures, from heavy clay to sandy loam, and grow well even in compacted soils. While they generally prefer moist, well-drained conditions, some varieties exhibit significant drought tolerance, allowing them to persist through dry spells. Foxtail Barley often colonizes sites that are seasonally wet, such as poorly drained pastures or the edges of drainage ditches, and tolerates saline and alkaline soils.
Foxtails flourish in full sunlight but can survive in partially shaded conditions, such as under thin turfgrass. The combination of high nutrient levels, particularly nitrogen, and soil disturbance creates an ideal habitat for prolific growth. Common locations where foxtail quickly dominates include abandoned lots, poorly maintained lawns, and overgrazed pastures.
Managing Foxtail in Specific Locations
The most effective management strategy for foxtail depends on the specific environment where it is growing. In established lawns and gardens, prevention focuses on creating a dense, healthy turf that blocks sunlight from reaching the soil and inhibiting seed germination. Homeowners can use pre-emergent herbicides containing active ingredients like prodiamine or pendimethalin in the early spring before the soil temperature triggers foxtail emergence.
For existing plants in gardens, hand-pulling is effective, but it must be done before the plant forms its characteristic seed head to prevent future infestations. Post-emergent selective herbicides can be applied to turfgrass to kill the foxtail while minimizing damage to the desired grass species. Since foxtail is an annual grass in these settings, preventing seed production for a few seasons can significantly deplete the seed bank in the soil.
In agricultural and pasture settings, control requires integrated methods such as crop rotation and timely tillage. Planting competitive crops like winter grains or alfalfa can suppress foxtail growth by shading the emerging seedlings. Tilling or using a rotary hoe to disrupt the soil surface when the foxtail is very small, ideally less than a quarter-inch tall, can kill the plants before they establish crown roots. For severe infestations, non-selective herbicides like glyphosate may be used to clear the area entirely before reseeding with competitive forage species.