Sand burrs are a widespread nuisance often encountered in lawns, parks, and open areas. These plants produce painful, spiny seed casings that readily attach to feet, clothing, and animal fur. Understanding the nature of this common weed is the first step in effectively managing its presence.
Physical Characteristics and Identification
Sand burrs are grasses belonging to the genus Cenchrus. This low-growing, warm-season grass often spreads out, forming dense mats of foliage. Its leaf blades are generally flat and twisted, sometimes exhibiting a reddish tint near the base of the stems.
The defining feature is the burr, the hardened fruit or seed casing that protects the seeds inside. These burrs are typically small, roughly a quarter-inch in diameter, and densely covered in sharp, stiff spines. Each burr contains one to three seeds and detaches easily once mature. The barbed spines allow the burr to cling tightly to anything that brushes past, facilitating wide dispersal.
Preferred Habitat and Life Cycle
This weed thrives in conditions where other plants struggle, favoring dry, sandy, and open soils, which is how it earned its common name. Sand burrs are frequently found in coastal regions, along roadsides, and in lawns or fields with poor soil health or sparse turf coverage. The plant is a summer annual, completing its life cycle within a single growing season.
Germination begins in the late spring and continues through the summer when soil temperatures reach approximately 52 degrees Fahrenheit. The grass grows actively throughout the warmer months, producing spiny burrs in late summer and early fall. The plant dies back after the first hard frost, but the mature burrs remain on the soil surface, ready to disperse seeds the following year.
Control and Removal Strategies
Effective control involves a multi-faceted approach combining mechanical, cultural, and chemical methods. For immediate removal, hand-pulling is effective, but must be done before the burrs mature to prevent seed dispersal. Mowing with a grass catcher can also help collect burrs before they fall to the ground.
Cultural control focuses on creating a dense, healthy lawn that naturally crowds out the weed. Proper fertilization and deep, infrequent watering encourage turf grass to establish a thick stand. This limits the open, disturbed soil that sand burrs prefer. You can also use a piece of burlap dragged across the ground to physically collect fallen burrs from infested areas.
Chemical treatment offers the most comprehensive solution, starting with pre-emergent herbicides. These products must be applied in the early spring to prevent the seeds from germinating. A second application six to eight weeks later is often recommended to manage the prolonged germination period. If the plants have already emerged, post-emergent herbicides are available for actively growing, young plants, though effectiveness decreases significantly as the burrs mature.