Foxtail is a common summer annual grass weed known for its rapid growth and ability to take over yards, creating a significant nuisance. The plant’s signature bristly seed heads pose a particular hazard to pets, as the barbed awns can become lodged in fur, ears, eyes, and noses, leading to serious medical issues. Stopping foxtails requires a comprehensive, multi-faceted strategy that combines timely physical removal, selective chemical applications, and long-term changes to lawn maintenance. Effective control focuses on preventing the plant from reaching maturity and producing the next generation of seeds.
Identifying the Target: Foxtail Lifecycle
Foxtails found in yards are typically summer annuals (e.g., green, yellow, giant foxtail), meaning they complete their life cycle in a single growing season. These weeds germinate from seed in the spring when soil temperatures consistently reach approximately 65 degrees Fahrenheit. This temperature threshold dictates the timing for preventative measures.
The plant grows through the summer, forming a coarse, upright bunch that competes with desirable turfgrass for resources. Foxtails begin to produce their characteristic spike-like seed heads from mid-summer until the first frost in the fall. Each mature plant can produce thousands of seeds, ensuring a dense population will return the following year if the seed heads are not managed. A less common type, like knotroot foxtail, is a perennial that can regrow from underground stems called rhizomes, requiring different control strategies.
Immediate Physical Removal Techniques
For small, isolated patches of foxtail, manual removal is an effective, non-chemical option, provided it is done before the plant sets seed. Hand-pulling is most successful when the soil is moist, as this allows the fibrous root system to be removed completely. If the plant is mature, using a trowel to dig out the entire clump, including the roots, is necessary to prevent regrowth.
Strategic mowing is a powerful tool to stop the weed’s reproductive cycle. Mowing should be timed to cut the seed heads off immediately after they emerge, before the seeds inside become viable. Since foxtail plants can quickly regenerate new seed heads, regular mowing every seven to ten days is often required to keep the plant suppressed.
The disposal of removed foxtail material must be handled carefully to avoid inadvertently spreading the seeds. These materials should be bagged, sealed, and removed from the property or sent to a municipal waste facility, as seeds can survive and be redistributed in a compost pile.
Chemical Control: Pre- and Post-Emergent Use
Chemical control involves using pre-emergent or post-emergent herbicides. Pre-emergent herbicides stop foxtail seeds from successfully germinating in the soil. These products, which often contain active ingredients such as pendimethalin, prodiamine, or dithiopyr, must be applied in early spring before the soil reaches the 65-degree Fahrenheit germination temperature.
The pre-emergent barrier is laid down on the soil surface and must be activated by irrigation or rainfall shortly after application to work correctly. Timing is crucial because applying it too late means the foxtail will have already sprouted, rendering the chemical ineffective. Pre-emergent herbicides prevent all seeds from sprouting, so they should not be applied if you plan to overseed your lawn.
Once foxtails are actively growing and visible, post-emergent herbicides are required to kill the established plants. For non-selective treatment in areas like sidewalks or driveways, a product containing glyphosate can be used, although this will kill all vegetation it contacts. Selective herbicides, such as those containing quinclorac or fenoxaprop-p-ethyl, are necessary in a lawn setting to target the foxtail grass without harming the desirable turf. Post-emergent treatments are most effective when applied to young, actively growing foxtail plants.
Long-Term Cultural Practices for Prevention
Stopping foxtail growth sustainably requires modifying the environment to favor healthy turfgrass. Foxtails thrive in thin, sparse, or disturbed soil, so improving soil health and density is a primary goal. This includes addressing soil compaction by aerating the lawn to improve water penetration and root growth.
Maintaining a dense stand of turfgrass effectively crowds out the weed seeds and prevents them from finding the necessary sunlight and space to germinate. This can be achieved through regular, balanced fertilization and overseeding the lawn with desirable grass species. By maintaining a slightly taller mowing height, you can encourage the turf to shade the soil, keeping it cooler and less hospitable for foxtail seed germination.
Proper water management also plays a significant role in making the area less inviting for foxtails. The goal is to water deeply but infrequently, promoting the growth of deep, extensive root systems in the turfgrass. Shallow, frequent watering keeps the topsoil moist, encouraging foxtail seed germination and growth. Avoiding overwatering helps deny the weed the conditions it needs to establish a foothold in the lawn.