The presence of clover, typically white clover (Trifolium repens), can disrupt the uniform appearance of a Zoysia lawn. Zoysia is a warm-season turf known for its dense growth and heat tolerance, but its sensitivity to certain broadleaf herbicides means clover removal requires a careful, two-pronged approach. Clover, a broadleaf perennial, often gains a foothold where the turf is weakened or soil conditions favor its growth. Eliminating clover and preventing its return depends more on establishing and maintaining superior Zoysia turf health than on a single chemical application.
Preparing Zoysia Grass for Clover Removal
A strong, healthy Zoysia lawn is the most effective natural defense against weed invasion. Before applying any treatment, cultural practices must be adjusted to favor the grass over the clover. Adjusting the mowing height is one of the quickest ways to create an inhospitable environment for low-growing weeds. Zoysia should be maintained at an optimal height of 1.5 to 2.5 inches, which is generally higher than many homeowners assume.
Mowing Zoysia at the upper end of this range allows the blades to cast enough shade onto the soil surface to suppress clover seed germination. This shading prevents the necessary sunlight from reaching the clover, which relies on light to establish itself in the dense turf. Furthermore, deep and infrequent watering encourages Zoysia to develop the extensive root system necessary for long-term health. Established Zoysia requires about one inch of water per week, delivered in a single or two deep soaking sessions every five to seven days.
Deep watering promotes robust Zoysia roots while discouraging the shallow root structure of clover, which thrives on frequent, light moisture. Clover is a legume that fixes atmospheric nitrogen, giving it an advantage in low-nitrogen turf. Proper fertilization, such as a quarter- to half-pound of nitrogen per 1,000 square feet every six weeks during the growing season, strengthens the Zoysia to outcompete the clover.
Manual and Organic Removal Methods
For small, isolated patches of clover, manual removal offers a direct, non-chemical solution. This method is most effective when the soil is moist, which allows the entire clover plant, including its deep taproot and surface-level stolons, to be pulled out completely. Leaving behind any part of the root system or the creeping stem can lead to rapid regrowth, making thorough removal paramount.
When spot-treating small areas, some homeowners utilize organic herbicides, such as concentrated horticultural vinegar. Vinegar with an acetic acid concentration of 10 percent or higher acts as a contact killer, desiccating the foliage of the clover. A drop of dish soap should be added to the mixture, as this acts as a surfactant, helping the solution adhere to the clover’s waxy leaves.
Apply these organic solutions with extreme precision, as they are non-selective and will damage or kill any Zoysia grass they contact. Since these treatments primarily affect the exposed leaves, multiple applications are often required to exhaust the plant’s root reserves. These methods are generally impractical for larger, widespread infestations.
Selecting Herbicides Safe for Zoysia
Chemical control for widespread clover requires selective post-emergent herbicides that target broadleaf weeds without damaging the Zoysia turf. Zoysia is sensitive to many common turf chemicals, making label reading a non-negotiable step. The most reliably safe active ingredients for Zoysia are combination products containing a mixture of phenoxy herbicides:
- 2,4-D
- Dicamba
- MCPP (mecoprop)
- Triclopyr
These synthetic auxins disrupt the broadleaf plant’s growth hormones, causing the weed to grow uncontrollably and perish.
Specifically, triclopyr is highly effective against clover and is a frequent component in specialized weed control products. When applying any post-emergent herbicide, timing and temperature are important for both efficacy and turf safety. Applications should only occur when temperatures are consistently between 65 and 85 degrees Fahrenheit, as cooler temperatures reduce effectiveness and higher temperatures increase the risk of Zoysia injury.
Allow the clover two to three days of undisturbed growth after mowing before application. This ensures maximum leaf surface area is available to absorb the herbicide. Conversely, certain herbicides, particularly those containing quinclorac (excellent for grassy weeds like crabgrass), must be used with extreme caution on Zoysia. While labeled safe, quinclorac can cause temporary yellowing or injury, especially if applied at excessive rates or during periods of high heat and humidity.
Long-Term Clover Prevention Strategies
Preventing clover recurrence requires correcting the underlying soil and cultural issues that allowed the weed to thrive. Since clover often indicates poor soil health, obtaining a professional soil test is the first step toward sustained prevention. The test results will reveal deficiencies in nutrients (like potassium or phosphorus) and highlight problems with soil pH.
Clover prefers conditions less than ideal for Zoysia, often establishing itself when the soil pH is too acidic. Applying lime based on soil test recommendations will raise the soil pH to the Zoysia-preferred range of 6.0 to 6.5, making nutrients more available to the turf. Addressing soil compaction through annual core aeration or dethatching is necessary, as Zoysia is prone to developing a thick thatch layer.
Aeration and dethatching improve the movement of air, water, and nutrients into the root zone, ensuring Zoysia can access its required resources. A dense turf canopy provides no room for clover seedlings to germinate. Maintaining a consistent fertilization schedule keeps the Zoysia vigorous and dense, allowing it to outcompete any new clover seeds that settle on the lawn surface.