How to Kill Spurge Weed in Lawn and Garden

Spotted spurge (Euphorbia maculata, also Chamaesyce maculata) and prostrate spurge (Euphorbia supina) are summer annual weeds that germinate in late spring and form dense, mat-like patches in lawns, beds, and cracks in pavement through summer. They are identifiable by a distinctive milky white sap that leaks from cut or broken stems and leaves, a reliable field identification characteristic shared by the Euphorbia genus. Spurge spreads rapidly from seed and a single plant can produce thousands of seeds in one season, so early control before seed set is critical.

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Identification

Growth habit: Prostrate, spreading from a central taproot. Stems radiate outward along the soil surface, forming a circular mat that can reach 12 to 18 inches across.

Leaves: Small, oval, opposite leaves. Spotted spurge typically has a reddish-purple blotch at the center of each leaf. Prostrate spurge lacks this spot and has slightly smaller leaves.

Milky sap: Break a stem or leaf, the white latex sap that immediately appears is the defining identification characteristic of spurge. Note that the sap can cause skin irritation in sensitive individuals.

Flowers: Tiny, inconspicuous pink-tinged flowers along the stems. Easily missed.

Season: Germinates in late spring when soil temperatures consistently exceed 60 degrees Fahrenheit. Most vigorous in summer. Killed by the first frost.

Pre-Emergent Control: Most Efficient Approach

Because spurge is an annual that regrows from seed each year, a correctly timed pre-emergent herbicide prevents the germination cycle before plants establish. This is the most efficient approach for lawns and beds with recurring spurge problems.

Timing: Apply pre-emergent in mid-spring before soil temperatures reach 60 degrees Fahrenheit, the germination threshold for spurge. In most of the US, this window aligns with or is slightly after the crabgrass pre-emergent window.

Effective active ingredients for spurge pre-emergent control:

Pendimethalin (Scotts Halts, Pendulum): Effective against spurge in lawns and garden beds
Isoxaben (Gallery): Effective against spurge and many other annual broadleaf weeds in bed areas and turf
Oxyfluorfen (Goal): Used in ornamental bed applications

In lawn areas, a spring weed and feed product containing pendimethalin addresses both crabgrass and spurge in the same application.

Post-Emergent Herbicide Control

For spurge plants that are already growing, post-emergent treatment is most effective on young plants before they have formed extensive mats and before seed set begins.

In Lawn Areas

Selective broadleaf herbicides containing 2,4-D, dicamba, and MCPP are effective on young spurge plants in turfgrass. Apply as a directed spray when spurge plants are small (fewer than six stems radiating from the center) and actively growing.

Products specifically labeled for spurge in turf include three-way broadleaf products (Spectracide Weed Stop, Ortho Weed B Gon). Apply when daytime temperatures are below 85 degrees Fahrenheit to avoid herbicide volatilization and turf stress.

In Beds and Non-Turf Areas

Glyphosate (non-selective) applied carefully as a directed spray is effective on spurge in bed areas where grass contact can be avoided. Apply to young plants before the mat forms. Use a shield or foam applicator when working near desirable plants to prevent drift.

Hand Removal

Spurge can be hand-pulled effectively when plants are young and before seed set. Pull the entire plant including the central taproot. Roots left in the soil often regenerate. Bag and dispose of pulled plants, do not compost, as seed can continue maturing after the plant is pulled.

Wear gloves when handling spurge, the milky latex sap causes contact dermatitis in some people.

Reducing the Seed Bank

Spurge seeds are persistent in the soil. In areas with established spurge populations, expect recurring germination for two to three seasons even after successful current-year control. Applying pre-emergent each spring progressively depletes the seed bank by preventing new seed from being added while the existing bank diminishes.

Dense turf coverage is the most effective long-term suppressant of spurge in lawn areas. Spurge establishes most readily in thin turf, compacted soil, and bare patches between established plants. Overseeding thin areas and maintaining correct fertility and mowing height reduces the soil surface openings that spurge exploits.