The appearance of sharp, spiny sand spurs, also known as sandburs, can quickly turn a lush lawn into a painful hazard for bare feet and pets. These persistent weeds indicate an underlying weakness in your turfgrass. Successfully eliminating these thorny pests requires a multi-pronged approach that targets the weed’s life cycle while protecting the health and density of your existing lawn. The strategies detailed here focus on precise timing and selective treatments to safely eradicate sand spurs without causing collateral damage to your grass.
Identifying the Culprit
Sand spurs belong to the Cenchrus species and are classified as warm-season annual grassy weeds. This means they complete their life cycle within a single growing season. During the vegetative stage, the plant has a coarse, light-green appearance that often blends seamlessly with desirable turfgrass. The sand spur plant grows in a clump or forms a mat, developing stems that are typically round and smooth.
The most recognizable feature is the spiny burr the plant produces from late spring through the summer and fall. These burrs are seed pods clustered near the tips of the stems, and each one can contain multiple seeds. Understanding this annual life cycle is important because the weed germinates from seed in the spring and continues to produce new seed until the first hard frost. Targeting the weed before it produces these seeds is the most effective method of control.
Preventing Sand Spurs: The Pre-Emergent Strategy
The most effective long-term method for sand spur control is stopping the germination of the seeds before they sprout. This is achieved by applying a pre-emergent herbicide, which creates a chemical barrier in the top layer of the soil. When the sand spur seed begins to germinate, the herbicide interferes with the cell division in the emerging roots and shoots, stopping the seedling from establishing itself.
Timing the application is based entirely on soil temperature, not the air temperature. Sand spur seeds begin to germinate when the soil temperature consistently reaches 52 to 55 degrees Fahrenheit. Applying the pre-emergent product just before this threshold ensures the barrier is in place to intercept the new seedlings. Monitor this temperature using a soil thermometer inserted three inches deep or by consulting local university extension resources.
Common active ingredients effective against sand spurs that are safe for most turfgrass include dithiopyr or pendimethalin. These selective herbicides target the grassy weed seedlings without harming established lawn grasses like Bermuda or Zoysia. Following application, the product must be “watered in” thoroughly, usually with about a half-inch of irrigation. This moves the chemical into the soil where the seeds are located, as failure to activate the product with water is a common reason for control failure.
Strengthening your turfgrass through cultural practices is a significant barrier to sand spur establishment. Sand spurs thrive in thin, stressed, or neglected lawns, especially those with sandy soil. Maintaining a dense lawn through proper fertilization, deep, infrequent watering, and mowing at the correct height helps the turf naturally choke out the weed. Mowing at the higher end of the recommended range for your grass species creates more shade at the soil level, which suppresses weed germination and growth.
Safe Removal: Post-Emergence Treatment Methods
Once sand spurs have visibly sprouted, they must be controlled with a post-emergent herbicide or mechanical removal, as pre-emergent products are no longer effective. Chemical removal requires the use of selective herbicides formulated to kill the target weed without damaging the surrounding turf.
For warm-season lawns like Bermuda or Zoysia, products containing thiencarbazone, iodosulfuron, and dicamba are often used for broad-spectrum control of grassy weeds. Atrazine is another option, specifically safe and effective for use on St. Augustine and Centipede grasses. Check the product label to confirm compatibility with your specific turf type before application, as using the wrong chemical can severely damage or kill the grass.
Post-emergent products are most effective when applied to young, actively growing sand spurs and when daytime temperatures are around 75 degrees Fahrenheit. Treating mature weeds that have already produced hardened burrs is significantly less effective. Always add a non-ionic surfactant to the spray mixture if the label recommends it. This additive helps the herbicide adhere to and penetrate the waxy surface of the weed leaves.
Mechanical Removal
For those seeking non-chemical solutions, mechanical removal is a reliable but labor-intensive option. Hand-pulling is feasible for small infestations, but the entire root system must be removed to prevent regrowth. To manage the spread of burrs, use a lawnmower with a bag attachment set at a low height to collect and remove the seed heads before they detach. A simple method involves dragging an old, fibrous blanket or towel across the lawn to snag the detached burrs, which can then be safely disposed of.