Spurge, a common and persistent summer annual weed, can quickly become a nuisance in home lawns. The most frequent culprit is spotted spurge, a fast-spreading plant that forms dense, unsightly mats across turf areas. It thrives in warm, sunny spots, particularly where the existing grass is thin or stressed. This article provides practical, layered strategies for both eliminating existing spurge and ensuring its recurrence is stopped before it begins.
Identifying Spurge and Its Growth Habits
Spurge is easily identified by its low, mat-like growth habit, which allows it to evade standard lawnmower blades. The stems are often reddish or pink, covered in fine hairs, and radiate outward from a central taproot. The small, dark green leaves are arranged opposite each other and may feature a distinctive maroon or purple spot in the center, especially in the spotted spurge variety.
A defining characteristic is the presence of a milky white sap. If a stem is broken, this sticky latex material will ooze out, which can be a mild irritant to human skin and eyes.
Spurge is a summer annual weed, meaning it germinates when soil temperatures rise to around 60°F. It grows rapidly throughout the warm season and dies with the first hard frost. A single plant is capable of producing thousands of seeds, which are often explosively dispersed and can remain viable in the soil for years.
Manual and Organic Removal Techniques
For small infestations, physically removing the spurge is an effective solution that avoids synthetic chemicals. Because the plant grows from a central taproot, hand-pulling is most successful when the soil is moist, allowing the entire root to be extracted cleanly. If the taproot breaks off, the remaining portion may sometimes regrow, so remove the plant before it sets seed.
When spurge appears in non-turf areas like cracks in pavement or patios, boiling water can be used as an organic spot treatment to kill the plant tissue on contact. Horticultural vinegar, which contains a higher concentration of acetic acid, can also be sprayed directly onto the weed to desiccate the leaves and stems. These contact treatments are non-selective, meaning they will also damage surrounding desirable plants, including turfgrass, so careful application is necessary.
Herbicides for Existing Spurge
For widespread infestations, a post-emergent herbicide is the most practical method for killing established spurge plants. These selective broadleaf weed killers are formulated to target the spurge without harming the surrounding turfgrass. The most effective products typically contain a combination of active ingredients, such as 2,4-D, dicamba, and MCPP (or MCPA).
These systemic herbicides are absorbed by the weed’s foliage and translocate throughout the plant, ultimately killing the roots. Newer formulations may also include triclopyr or sulfentrazone for enhanced control, especially against mature weeds.
Applying the post-emergent herbicide when the spurge is actively growing, typically during warmer periods, yields the best results. A second treatment is often necessary two to three weeks after the initial application, as mature spurge can be resilient. Always consult the product label to ensure the herbicide is safe for your specific grass type and follow all instructions regarding application rates and safety.
Preventing Spurge Recurrence
Stopping spurge before it sprouts requires a combination of chemical and cultural controls. The primary chemical method involves applying a pre-emergent herbicide, which creates a barrier in the soil that prevents spurge seeds from germinating. Timing is crucial: the herbicide must be applied before the soil temperature consistently reaches 55°F to 60°F, when spurge seeds begin to sprout.
Common pre-emergent active ingredients include prodiamine, dithiopyr, and pendimethalin. After application, the product must be lightly watered into the soil to activate the barrier, which typically remains effective for eight to twelve weeks.
Beyond chemical treatments, cultural practices are essential for long-term prevention by promoting a dense, healthy lawn. Mowing the grass at a higher setting (three to four inches) shades the soil surface, inhibiting the light-dependent germination of spurge seeds. Proper irrigation and fertilization also strengthen the turf, allowing the grass to crowd out new spurge seedlings.