Prostrate spurge is a common, aggressive summer annual weed that invades lawns, gardens, and sidewalk cracks. Its low-growing, mat-forming nature evades typical lawnmowers, and prolific seed production ensures a continuous battle. Eliminating this persistent invader requires a comprehensive strategy targeting the weed at every life cycle stage. Permanent removal involves accurate identification, manual removal, precise chemical application, and long-term cultural changes.
Identifying Prostrate Spurge and Its Growth Habits
Accurate identification is the first step in effective management. The weed is characterized by its prostrate, or ground-hugging, growth habit. Reddish stems branch out from a central taproot, forming dense, circular mats up to 16 inches in diameter. Leaves are small, pale green, and egg-shaped, often featuring a distinct maroon watermark or spot near the center.
A key identifying feature is the white, milky sap that oozes out when the stems or leaves are broken, which can be irritating to the skin. As a summer annual, prostrate spurge germinates when soil temperatures consistently reach 60 to 65 degrees Fahrenheit, typically in mid-to-late spring. It is a rapid grower, capable of producing new seeds within five weeks of germination, leading to multiple generations until the first hard frost kills the plant.
Manual and Organic Eradication Techniques
For small infestations or young plants, manual removal is the most direct and effective method. The weed has a shallow taproot, making it easy to pull when the soil is moist. Grip the plant firmly near the base and remove the entire taproot to prevent regrowth.
Wearing gloves is recommended due to the irritating milky sap released when the plant is broken. Dispose of removed plants in the trash, not composted, to prevent seed spread. Organic spot treatments, such as boiling water or horticultural vinegar, can be used in non-lawn areas. These treatments are non-selective and will harm desirable plants, so they are best reserved for sidewalk cracks or driveways.
Choosing and Applying Chemical Treatments
Chemical control is most effective using a two-pronged approach combining pre-emergent and post-emergent herbicides. Pre-emergent herbicides prevent seeds from germinating and should be applied in early spring when soil temperatures approach 55 to 60 degrees Fahrenheit. Active ingredients such as prodiamine, dithiopyr, or isoxaben are recommended for creating a chemical barrier that stops seedling roots from developing.
For existing, actively growing spurge, a post-emergent herbicide is necessary, ideally when temperatures are between 60 and 85 degrees Fahrenheit. Look for products containing 2,4-D, dicamba, and triclopyr, which target broadleaf weeds without harming most turfgrasses. Adding a surfactant helps the herbicide penetrate the spurge’s thick, waxy cuticle, improving effectiveness. Spot-treating individual weeds is safer than broadcasting the chemical, and always follow label instructions regarding temperature restrictions.
Cultural Practices for Long-Term Control
The most durable defense against prostrate spurge is creating a dense, healthy turf that outcompetes the weed. Increasing the mowing height to between 3 and 4 inches shades the soil surface, which is crucial because spurge seeds require sunlight to germinate. Taller grass also builds a more robust root system, making the lawn less susceptible to invasion.
Adjusting irrigation practices is equally important, as spurge thrives in moist soil created by shallow, frequent watering. Shifting to deep and infrequent watering encourages grass roots to grow deeper and makes the surface soil drier and less welcoming to spurge seeds. Addressing soil compaction through core aeration can limit the weed’s ability to establish itself, as spurge prefers poor drainage and low oxygen levels. These cultural practices, combined with timely physical and chemical controls, form a sustained defense to eliminate the weed.