White clover (Trifolium repens) is a common, mat-forming perennial found in lawns and gardens across North America. As a legume, it partners with soil bacteria to pull nitrogen from the atmosphere and convert it into a usable nutrient within its root nodules. This nitrogen fixation allows clover to flourish in nutrient-poor soils where turfgrass struggles, quickly establishing dense patches by spreading through creeping stems (stolons) that root along the ground. Removing clover and preventing its return involves a dual approach of direct eradication and long-term soil health management.
Non-Chemical Removal Techniques
For small, isolated clover patches, manual removal is an effective, non-chemical solution. The root system of the clover must be entirely extracted, which is easiest when the soil is moist. Loosening the soil with a trowel before pulling helps ensure the entire root and the creeping stems, called stolons, are removed to prevent regrowth.
Another method for larger patches involves smothering the plant by depriving it of sunlight. This process, often called solarization, requires covering the affected area with an opaque material like black plastic sheeting or thick layers of mulch for several weeks. Blocking the sun starves the clover of the energy needed for survival, causing the entire patch to die back.
Adjusting cultural practices can also prevent clover from establishing itself. Mowing the lawn at a higher setting, typically between three and four inches, encourages the grass blades to grow taller. This increased height shades the soil surface, making it difficult for clover seeds to germinate and for existing clover to receive enough light to thrive.
For spot treatment, a solution containing concentrated horticultural vinegar can be sprayed directly onto the clover leaves. Household vinegar is generally too weak, so a product with 20% to 30% acetic acid is needed to scorch the foliage effectively. Because this solution is non-selective, it will damage any plant it touches, so caution is needed to avoid spraying surrounding desirable plants.
Targeted Herbicide Application
When clover is widespread, a chemical treatment using a selective broadleaf herbicide is often the most practical solution for a lawn setting. Products formulated to target broadleaf weeds will contain active ingredients such as 2,4-D, dicamba, MCPP (Mecoprop), or triclopyr. These selective formulas kill the clover without harming the majority of common lawn grasses.
The application must be timed carefully to maximize effectiveness and safety. Herbicides work best when the clover is actively growing, typically during the spring or fall, and should not be applied during periods of extreme heat or drought. Apply the product on a calm, warm day when temperatures are below 90°F to prevent drift and volatilization.
In garden beds or areas without turfgrass, non-selective herbicides, such as those containing glyphosate, can be used as a targeted spot treatment. However, these chemicals will kill virtually any plant they contact, requiring precise application to avoid damaging flowers or vegetables. Always follow the manufacturer’s instructions for application rates and safety precautions specific to the product and the target plant.
Maintaining a Clover-Free Garden
The most effective long-term strategy for a clover-free garden is to address the underlying cause of its presence: a deficiency of nitrogen in the soil. Clover thrives when turfgrass is weak, so regular application of a high-nitrogen fertilizer will support a dense, healthy lawn that naturally outcompetes the weed. Increasing soil fertility removes the advantage clover gains from its ability to fix nitrogen.
Implementing proper watering techniques also encourages the growth of deep-rooted, competitive grass. Watering deeply but infrequently strengthens the turf’s root system, making it more resilient against shallow-rooted weeds like clover. Frequent, shallow watering, conversely, keeps the soil surface moist and favors the establishment of new clover plants.
Improving the physical condition of the soil through core aeration helps to loosen compacted ground, which is another environment clover tolerates well. Following aeration, over-seeding with a suitable turfgrass variety will increase the density of the lawn. A thick, healthy stand of grass crowds out available space, preventing the germination and spread of clover seeds and stolons.