Sand spurs (Cenchrus species) are annual weeds that thrive in dry, sandy, or disturbed soils across warm-season climates. They are notorious for producing sharp, spiny seed heads, or burs, which easily cling to clothing, pet fur, and bare skin, causing painful irritation. These tough seed capsules harbor multiple seeds and persist in the soil for long periods, leading to recurring infestations. Eradicating this persistent weed requires a comprehensive strategy combining timely chemical applications with physical removal and long-term turf management practices.
Manual and Non-Toxic Removal Techniques
For small infestations or areas where chemical use is not desired, physical removal methods offer an immediate solution. Hand-pulling is the most direct approach, but protective gloves are required to avoid the painful spines. The entire plant, including the root system, must be removed to prevent regrowth, which is easier after deep watering when the soil is soft.
A scuffle hoe can cut the sand spur just below the soil line, severing the plant from its roots. To prevent seed spread, carefully remove and bag any mature burs before disturbing the plant. Loose burs can be collected by dragging an old blanket or towel across the area for safe disposal. Solarization, covering small areas with clear plastic sheeting during hot weather, uses heat to kill existing plants and seeds beneath the surface.
Chemical Control Strategies
Widespread sand spur infestations often rely on the strategic use of herbicides, categorized as pre-emergent and post-emergent types. Pre-emergent herbicides are the most effective, creating a barrier in the soil that prevents seeds from germinating. Common active ingredients include prodiamine, pendimethalin, and dithiopyr. These products must be watered into the soil immediately after application to activate the barrier that stops emerging seedlings.
Post-emergent herbicides kill sand spur plants that are already visible above the soil line. These products are best applied when the sand spurs are young and actively growing, before they produce mature, spiny burs. Active ingredients used for control on warm-season turfgrasses include imazaquin and a combination of thiencarbazone, iodosulfuron, and dicamba. Non-selective herbicides containing glyphosate can be used only in non-turf areas, as they kill all surrounding vegetation. Always wear appropriate personal protective equipment (PPE) and strictly follow label directions, paying attention to application rates and safety restrictions.
Timing Applications for Maximum Effectiveness
Successful sand spur eradication depends on the precise timing of application, which must align with the plant’s life cycle. As a warm-season annual, its seeds germinate in the spring, and the plant dies with the first hard frost. The window for applying pre-emergent herbicides is narrow and must occur before the seeds begin to sprout.
Germination typically starts when the soil temperature consistently reaches 52 to 55 degrees Fahrenheit at a four-inch depth. Tracking soil temperature is more reliable than relying on air temperature or calendar date. Applying pre-emergent too late means the sand spurs have already germinated, rendering the product ineffective. For heavy infestations, a second application 6 to 8 weeks after the first extends residual control. Post-emergent treatments should target young plants in late spring or early summer, as mature, seed-setting plants are harder to kill.
Long-Term Prevention and Lawn Management
Long-term control focuses on cultural practices that create a dense, healthy turf, which crowds out weeds like sand spurs. Sand spurs thrive in bare spots and thin turf.
Mowing and Fertilization
Correct mowing height is a significant factor in prevention. Keeping the grass at the upper end of the recommended height maintains dense foliage that blocks sunlight from reaching the soil surface. Proper fertilization based on a soil test ensures the turf receives necessary nutrients for vigorous growth, allowing it to outcompete weeds.
Watering Practices
Watering should focus on deep, infrequent irrigation rather than light, frequent sprinkles. Deep watering encourages a strong, deep root system in the turfgrass. Shallow watering creates a constantly moist surface that favors sand spur seed germination. Filling in any thin or bare patches with new sod or grass plugs also eliminates open ground where sand spurs prefer to establish themselves.