Lawn Care
What Kills Clover in Lawns? Proven Herbicide & Organic Solutions
The Quick Answer: The most effective chemical killers for clover in lawns are selective, systemic broadleaf herbicides containing a three-way mix of Dicamba, MCPP-p (Mecoprop), and 2,4-D. For organic eradication, raising soil nitrogen levels, manual stolon extraction, and applying Corn Gluten Meal (CGM) as a pre-emergent are the only proven methods.
Why Clover Invades: Reading the Soil Signals
Clover is rarely just a random weed; it is a biological indicator of specific soil deficiencies. Before asking what kills clover in lawns, you must understand why it thrives where your turfgrass fails. Clover is a legume, meaning it hosts Rhizobium bacteria in its root nodules, allowing it to fix atmospheric nitrogen. If your lawn soil is nitrogen-deficient, compacted, or has a high phosphorus-to-nitrogen ratio, clover will rapidly outcompete your grass.
According to the University of California Statewide IPM Program, clovers thrive in poorly maintained turf with low nitrogen fertility. Eradicating the visible plant without correcting the soil ecology guarantees a reinvasion within one growing season.
Identifying Your Clover Type
Accurate identification dictates your chemical approach. While most broadleaf herbicides work across the Trifolium genus, the growth habit changes how you apply them.
| Clover Species | Growth Habit | Key Identifier | Herbicide Susceptibility |
|---|---|---|---|
| White Clover (T. repens) | Creeping stolons | White V-shaped leaf markings; white/pink spherical flowers | High (Systemics translocate through stolons) |
| Red Clover (T. pratense) | Upright, bushy | Large hairy leaves; red/purple elongated flowers | Moderate (Requires higher herbicide rates) |
| Hop Clover (T. campestre) | Low creeping | Small yellow flowers resembling miniature hops | High (Easily controlled with 2,4-D blends) |
Chemical Controls: What Actually Kills Clover?
Many homeowners buy generic 'weed and feed' products containing only 2,4-D and wonder why the clover returns. 2,4-D alone causes leaf cupping in clover but rarely kills the deep taproot or extensive stolon network. To permanently kill clover, you need a synergistic three-way herbicide formulation.
The Prosumer Herbicide Matrix
Below are the industry-standard formulations that effectively kill clover without harming common cool-season (Fescue, Kentucky Bluegrass) and warm-season (Bermuda, Zoysia) turfgrasses.
Pro Tip: The Surfactant Requirement
Clover leaves possess a thick, waxy cuticle that repels water-based sprays. If you are mixing liquid concentrates, you must add a Non-Ionic Surfactant (NIS) at a rate of 0.25% v/v (roughly 1 teaspoon per gallon of water). This breaks the surface tension, allowing the active ingredients to penetrate the leaf tissue.
Clover leaves possess a thick, waxy cuticle that repels water-based sprays. If you are mixing liquid concentrates, you must add a Non-Ionic Surfactant (NIS) at a rate of 0.25% v/v (roughly 1 teaspoon per gallon of water). This breaks the surface tension, allowing the active ingredients to penetrate the leaf tissue.
- PBI/Gordon's SpeedZone Broadleaf Herbicide: The gold standard for professional turf managers. Contains 2,4-D, MCPP-p, Dicamba, and Carfentrazone-ethyl. The addition of Carfentrazone provides rapid 'burn-down' of the foliage within 24 hours, while the other three ingredients systemically kill the roots over 14 days. Application Rate: 2.5 to 3.5 fl oz per 1,000 sq ft. Cost: ~$135 per gallon (covers up to 50,000 sq ft).
- Ortho WeedClear Lawn Weed Killer (RTU): A ready-to-use consumer option containing 2,4-D, Quinclorac, and Dicamba. Quinclorac is highly effective against clover and also targets grassy weeds like crabgrass. Application Rate: Spray to wet. Cost: ~$16 for a 32 oz spray bottle (covers ~5,000 sq ft).
- Bayer BioAdvanced Season Long Weed Control: Formulated with Isoxaflutole and active broadleaf killers. Best used as a preventative early spring application rather than a post-emergent knockout.
Ester vs. Amine Formulations: Timing Matters
Herbicides come in two primary chemical salt forms. Amine formulations are water-soluble and work best in warm weather (70°F–85°F). Ester formulations (like SpeedZone) are lipid-soluble, meaning they easily penetrate the waxy clover leaf even in cool spring or fall temperatures (45°F–65°F). If you are treating clover in early April or late October, an ester-based product is mandatory for success.
Organic & Cultural Eradication Methods
If you maintain an organic lawn or have pets and children that restrict chemical use, killing clover requires a multi-pronged cultural approach. The Penn State Extension notes that organic weed management relies heavily on altering the environment to favor turfgrass over legumes.
1. Nitrogen Loading
Clover fixes its own nitrogen; turfgrass does not. By applying a high-nitrogen organic fertilizer like feather meal (12-0-0) or blood meal (12-0-0) at a rate of 1 lb of actual nitrogen per 1,000 sq ft every 6 weeks during the growing season, you force the grass to grow thick and dense. This dense canopy shades out the low-growing clover stolons, effectively starving them of sunlight.
2. Corn Gluten Meal (CGM) Pre-Emergent
CGM will not kill existing clover plants, but it inhibits seed germination. Since white clover spreads heavily by seed in late summer, applying CGM in early spring and early fall prevents the seed bank from expanding. Required Rate: 20 lbs per 1,000 sq ft. Cost: ~$45 for a 50 lb bag. Note: CGM contains about 10% nitrogen, so it doubles as a mild fertilizer.
3. Manual Stolon Extraction
Pulling the flower heads does nothing. You must use a weeding tool, such as the Fiskars Stand-Up Weeder or a traditional dandelion fork, to sever the stolon network beneath the soil surface. If a 2-inch segment of stolon with a node remains in the soil, it will regenerate a new plant within 10 days.
Post-Eradication Lawn Recovery Protocol
Once the clover is dead, you are left with bare patches of soil. If left alone, new weed seeds (like spurge or dandelion) will fill the void. Follow this 3-step recovery protocol:
- Rake and Scarify: Wait 14 days after herbicide application. Use a metal tine rake to aggressively remove the dead clover thatch and scratch the top 1/4 inch of the soil.
- Overseed with Competitive Cultivars: Apply a high-quality, shade-tolerant turf-type tall fescue (for cool-season lawns) or sow Bermuda seed (for warm-season lawns) at 5 lbs per 1,000 sq ft. Look for NTEP-rated (National Turfgrass Evaluation Program) cultivars that score high for lateral density.
- Top-Dress and Water: Apply a 1/4 inch layer of fine compost over the seed. Water lightly twice daily for 14 days to ensure germination, then transition to deep, infrequent watering to drive roots downward.
Clover Control FAQ
Will vinegar kill clover?
Horticultural vinegar (20% to 30% acetic acid) will burn the foliage of the clover, but it is a contact herbicide, not a systemic one. The roots and stolons will survive and push up new growth within a week. Furthermore, high-concentration vinegar is highly corrosive, dangerous to handle, and will temporarily sterilize the soil microbiome.
Is it bad to have some clover in the lawn?
Not necessarily. Many ecological landscaping experts now advocate for 'micro-clover' blends. Clover stays green during summer droughts, requires zero nitrogen fertilizer, and provides vital nectar for pollinators. If you can tolerate a mixed sward, maintaining a 10% to 15% clover ratio can actually reduce your lawn's water and fertilizer requirements.
How long does it take for SpeedZone to kill clover?
You will see visible wilting and leaf curling within 12 to 24 hours due to the Carfentrazone. However, complete root death and total browning of the clover patch typically takes 10 to 14 days. Do not reapply or mow the area for at least 7 days post-spray to allow maximum translocation of the active ingredients into the root zone.
