Burr weeds, often called sticker weeds or spurweeds, are low-growing invaders whose painful, spine-tipped seed pods can quickly turn a lawn into a minefield. They spread rapidly and cling to anything that brushes past them, including bare feet and pet fur. Successfully eliminating these nuisance plants requires a strategic approach that combines timely removal with long-term prevention. Understanding the burr weed’s specific growth cycle is the foundation for an effective eradication plan.
Recognizing Burr Weeds and Their Life Cycle
Lawn Burweed (Soliva sessilis) is the most common culprit and is a winter annual, dictating a specific treatment schedule. It germinates in thin patches of turf during the cooler autumn and early winter months. The plant remains small and inconspicuous, growing low to the ground throughout the cold season.
As spring temperatures rise, the weed enters a phase of rapid growth and produces small, greenish, spine-tipped burrs. These burrs contain the seeds for the next generation. Once the burrs form and harden, killing the plant will not eliminate the sharp stickers already present in the lawn. The plant dies off naturally when summer temperatures climb above 90 degrees Fahrenheit, leaving the painful burrs behind to germinate the following fall.
Non-Chemical Removal Methods
For small, isolated patches, physical removal is an immediate, non-chemical solution. The best time for hand-pulling is during late fall or winter when the plants are small and have not yet developed hard, spiny burrs. If removing plants with mature burrs, carefully bag the weeds to prevent spreading seeds across the lawn.
Non-synthetic methods can address larger problem areas. Applying concentrated horticultural vinegar acts as a contact herbicide to desiccate the above-ground foliage. This approach may require repeat applications and is most effective on young weeds, but it will not eliminate the root system of a mature plant. For highly infested areas, soil solarization involves covering the area with clear plastic sheeting during hot weather to raise soil temperatures high enough to kill the weed and its seeds.
Selecting and Applying Herbicides
Chemical control is most effective when timed precisely to the burr weed’s life cycle, focusing on prevention before the painful burrs form. The most successful strategy involves a dual approach using both pre-emergent and post-emergent herbicides.
Pre-Emergent Application
Pre-emergent herbicides are applied in the fall, typically in late September to early October, when nighttime temperatures consistently drop into the 55 to 60-degree Fahrenheit range. This application prevents the winter annual seeds from germinating, effectively reducing the weed population for the following spring. Effective pre-emergent options include products containing active ingredients like prodiamine, dithiopyr, or isoxaben.
Post-Emergent Application
If the fall window is missed, post-emergent herbicides can be used during the winter months (December through February) when the weed is actively growing but still young. Effective post-emergent products are broadleaf weed killers containing compounds such as 2,4-D, dicamba, or mecoprop (MCPP). Formulations with a higher concentration of dicamba and MCPP are generally more effective against burr weed than those relying heavily on 2,4-D alone. Applying a non-ionic surfactant with the liquid herbicide can improve control by helping the product stick to the weed’s low-lying leaves. Always read the product label carefully, as certain herbicides like atrazine are safe only for specific turf types, such as St. Augustinegrass and Centipedegrass.
Strategies for Long-Term Prevention
Long-term control requires creating an environment where burr weeds cannot thrive. Burr weeds are opportunists that primarily infest weak, thin, or stressed turf. Improving the density of the lawn is a highly effective cultural practice for prevention.
Conducting a soil test to determine the nutrient and pH balance of your lawn is an important step, as burr weeds often prefer areas with poor soil health or compaction. Correcting imbalances with appropriate fertilizers and lime encourages turfgrass to become thicker, naturally crowding out germinating weed seeds. Adjusting cultural practices like mowing and watering will also favor the grass over the weed.
Mowing at the correct height for your specific turf type encourages deep root growth and a dense canopy that shades the soil, inhibiting weed seed germination. Watering deeply and infrequently promotes a healthier root system for the grass, making it more competitive against weeds. A healthy, dense lawn is the best defense, as strong turfgrass will outcompete the burr weed for light, water, and essential soil nutrients.