White clover (Trifolium repens) is a common perennial broadleaf plant that often invades home lawns. It thrives in conditions where turfgrass struggles, particularly in soil with low nitrogen levels. As a legume, clover fixes atmospheric nitrogen into a usable form, essentially creating its own fertilizer. This gives it a significant advantage over grass in poor soil, indicating the lawn is nitrogen-starved or unhealthy. Successful removal requires a two-part strategy: eliminating existing patches and implementing long-term cultural practices to prevent its return.
Non-Chemical Removal Techniques
For smaller, isolated clover patches, immediate removal without synthetic chemicals is a viable option that targets the plant directly. Hand-pulling is effective, but it requires diligent effort to ensure the complete removal of the root system. White clover is a creeping perennial that can root at its stem nodes, so breaking off the above-ground foliage will only offer temporary relief. To prevent immediate regrowth, the soil should be moistened before pulling, which helps the entire root mass slide out more easily from the ground.
For larger, dense areas, a smothering technique can kill the clover and underlying grass by eliminating light. Placing heavy, opaque material like black plastic sheeting or layers of thick newspaper over the affected area blocks photosynthesis, starving the plants beneath. This process can take several weeks, but it effectively kills all vegetation in the covered patch. The drawback is that this method is non-selective, meaning the turfgrass will also be killed, requiring reseeding afterward.
Another non-chemical option is the targeted application of concentrated horticultural vinegar, which uses acetic acid as a contact herbicide. Household vinegar (5% acetic acid) is too weak; effective control requires horticultural varieties containing 20% to 30% acetic acid. This acid rapidly dehydrates the clover’s foliage by destroying cell walls, causing the leaves to shrivel quickly. Since vinegar is non-selective and only burns the parts it touches, it must be applied carefully to avoid damaging surrounding turfgrass. Repeat applications are often necessary because it typically does not penetrate to kill the root system of mature plants.
Selective Herbicide Application
When a clover infestation is widespread or too stubborn for non-chemical methods, selective herbicides offer a solution that targets the broadleaf weed while leaving the turfgrass unharmed. The most effective products for white clover contain a combination of active ingredients, often referred to as three-way herbicides. Look for formulations that include 2,4-D, MCPP (mecoprop), and Dicamba, as these compounds work synergistically to provide a higher degree of control.
These selective products are absorbed by the clover and act as plant growth regulators, disrupting the weed’s normal hormone balance. The optimal time for application is when the clover is actively growing, either in the early spring or, preferably, in the fall. Fall application allows the herbicide to be efficiently translocated down to the root system as the plant prepares for winter, leading to better long-term elimination.
Applying the product as a spot treatment, rather than a broad broadcast, is recommended for smaller patches to minimize the chemical footprint on the lawn. Always follow the manufacturer’s instructions precisely regarding mixing ratios and dilution to ensure the product is effective without damaging the grass. Adding a surfactant, such as liquid dish soap, can help the herbicide stick to the clover’s waxy leaves. This increases absorption and overall efficacy.
Cultural Practices for Long-Term Control
Promoting a dense, healthy lawn that naturally crowds out weeds is the best long-term defense against white clover. Clover is an opportunistic weed that thrives in low-fertility soil, making fertilization adjustments a high-impact strategy. Applying a nitrogen-rich fertilizer regularly shifts the competitive balance back to the grass, which requires external nitrogen sources to flourish. This fuels the turfgrass, creating an environment where the clover’s nitrogen-fixing ability no longer provides a survival advantage.
Changing your mowing height is an effective cultural control practice. Maintaining a taller turf height, typically between 3 and 4 inches, helps shade the soil surface. This shading prevents sunlight from reaching low-growing clover seedlings, inhibiting their ability to germinate. Taller grass blades also encourage deeper, stronger grass roots, making the lawn more resilient to weed encroachment.
Proper watering practices further strengthen the turfgrass against clover invasion. Deep, infrequent watering encourages the grass to develop extensive, deep root systems. Since white clover has a relatively shallow root system, deep watering makes the upper soil less hospitable for the clover while benefiting the grass. Finally, consider a soil test to identify and correct underlying issues, such as extreme soil pH or severe compaction. These factors create conditions where clover is more likely to thrive than grass.