Prostrate spurge (Euphorbia maculata or spotted spurge) is a common summer annual weed that spreads aggressively across bare soil and thin turf areas. It branches out from a central taproot, creating dense patches that can quickly smother desirable grasses and ornamental plantings. Control is difficult due to its reproductive efficiency; plants can begin producing viable seeds in as little as five weeks. These seeds germinate rapidly throughout the warm season, meaning multiple generations may appear in a single year. Effective eradication requires an integrated approach, utilizing both physical and chemical methods to break the weed’s life cycle.
Immediate Physical Removal and Cultural Suppression
For small, isolated patches, physically removing the weed is effective, provided the entire root system is extracted. Prostrate spurge develops a thick taproot that must be completely removed to prevent the plant from regrowing. The best time for manual removal is when the soil is moist, which allows for easier extraction. Wearing protective gloves is advisable, as the stems and leaves exude a milky white sap that can cause skin irritation.
Maintaining a dense, healthy turf that outcompetes the spurge for sunlight and nutrients is essential. Mowing grass at a higher setting (three to four inches) shades the soil, inhibiting the germination of spurge seeds that require light to sprout. Deep but infrequent watering encourages the turfgrass to develop a robust root system while discouraging the spurge’s shallow rooting habit. In non-turf areas, applying a thick layer of organic mulch or utilizing landscape fabric suppresses growth by blocking light and creating a physical barrier.
Post-Emergent Chemical Eradication
When prostrate spurge has already emerged, selective post-emergent herbicides can be used to kill the actively growing plants without harming the surrounding turfgrass. Effective control involves products containing a combination of broadleaf active ingredients, such as 2,4-D, dicamba, and triclopyr. These ingredients target the weed’s broad leaves, providing a systemic kill that moves down to the taproot. Sulfentrazone and MCPA are also frequently included in multi-way selective herbicides used for this purpose.
Application requires careful timing and technique, especially since the spurge’s leaves and stems develop a waxy coating as the plant matures. Adding a non-ionic surfactant or spreader-sticker to the herbicide mixture helps the chemical penetrate this barrier. Apply these chemicals when temperatures are moderate; high temperatures (exceeding 85°F) can cause ingredients to volatilize, increasing the risk of drift and damage to desirable plants. Always follow the product label instructions precisely and use appropriate personal protective equipment (PPE) when mixing and applying herbicide.
Stopping Prostrate Spurge Before It Starts
Prevention using pre-emergent herbicides is the primary long-term strategy against prostrate spurge, as these chemicals target the weed before it becomes visible. As a summer annual, spurge seeds germinate when the soil temperature consistently reaches approximately 60 degrees Fahrenheit. The protective chemical barrier must be in place before this germination window opens.
Pre-emergent products must be applied in the early spring, typically when the five-day average soil temperature is below 55 degrees Fahrenheit. Common active ingredients like Prodiamine or Dithiopyr work by inhibiting cell division in the newly germinated seeds, stopping the weed from developing a root system. Timing the application correctly is paramount, as applying the product too late, after the seeds have already sprouted, renders the pre-emergent ineffective.