The presence of clover, a broadleaf weed belonging to the Trifolium genus, can quickly disrupt the uniform appearance of a turfgrass lawn. This resilient plant often signals underlying issues with soil health, allowing it to compete successfully against desirable grasses. While some homeowners tolerate clover, many seek effective strategies to eliminate it and restore a consistent lawn aesthetic. Understanding the plant is the first step toward successful removal.
Proper Identification of Purple Clover
The plant commonly referred to as “purple clover” is most often Red Clover (Trifolium pratense) or, less frequently, Crimson Clover (Trifolium incarnatum). Red Clover is a perennial or biennial plant distinguished by its fuzzy stems and purple-red flower heads. Each leaf consists of three leaflets, often displaying a pale green or whitish chevron marking on the surface.
While White Clover (Trifolium repens) produces white or creamy-pink flowers, its foliage can sometimes take on a reddish hue under stress, leading to confusion. Proper identification matters because Red Clover has a deep taproot, which requires different removal techniques than the creeping stolons of White Clover. Clover thrives in soil environments where turfgrass struggles, particularly those with low nitrogen levels and compacted conditions.
Mechanical and Organic Removal Methods
For small, isolated patches of clover, mechanical removal is a highly effective, non-chemical option. Hand-pulling is most successful when the soil is moist, as this allows the entire root structure to be removed intact. Since Red Clover develops a significant taproot, grasp the plant firmly at the base and pull slowly to prevent the root from breaking off and allowing regrowth.
Another organic method involves depriving the clover of sunlight, which works well for localized infestations. Covering the patch with an opaque material, such as black plastic or heavy mulch, will block photosynthesis and kill the plants underneath within a few weeks. This smothering technique is best applied to areas where the surrounding turfgrass is sparse.
Household solutions can be employed for targeted spot treatments, such as concentrated vinegar with an acetic acid concentration of at least 10%. This solution acts as a desiccant, scorching the leaves of the broadleaf weed upon contact. However, the high acidity can also damage turfgrass, necessitating careful application directly onto the clover foliage. Iron-based weed control products are available that selectively dry out and darken the clover without harming the surrounding grass.
Effective Herbicide Strategies
For widespread infestations, chemical control using a selective broadleaf herbicide is the most efficient method to eradicate clover. Selective herbicides are formulated to target broadleaf plants, like clover, while leaving turfgrasses largely unaffected. The most effective products for clover control generally contain a combination of active ingredients, such as 2,4-D, MCPP (mecoprop), and Dicamba.
These combination products work by disrupting the clover’s growth hormones, causing uncontrolled growth that leads to plant death. Application timing is an important factor in maximizing effectiveness, with fall applications often providing the most thorough control. Treating clover in the fall allows the herbicide to be efficiently translocated down to the root system as the plant prepares for winter dormancy.
Spring applications are acceptable, but treatment should occur when the clover is actively growing and temperatures are moderate, ideally between 60°F and 85°F. Wait at least two days after mowing before applying the herbicide, which allows the leaves to regrow and maximize absorption of the chemical. Spot treating individual patches is preferred over broadcast application across the entire lawn, as this minimizes overall chemical use.
Always follow the manufacturer’s instructions precisely, especially regarding mixing rates and personal protective equipment. Avoid applying herbicides during windy conditions to prevent drift onto non-target plants. Keep children and pets off the treated area until the product has completely dried, which usually takes about 24 hours. For recurring problems, pre-emergent herbicides containing active ingredients like Isoxaben can be applied in spring and fall to prevent clover seeds from germinating.
Adjusting Lawn Care to Prevent Recurrence
Eradicating existing clover is only a temporary fix unless the underlying soil and maintenance conditions are addressed, as clover thrives where grass is weak. Clover is a legume that draws nitrogen from the air and converts it into a usable form in its root nodules, giving it a significant advantage in nitrogen-poor soil. The single most impactful long-term change is implementing a consistent nitrogen fertilization program.
Regular application of a nitrogen-rich fertilizer strengthens the turfgrass, allowing it to outcompete the clover for resources like water and sunlight. This encourages a dense, vigorous lawn that naturally shades the soil and suppresses weed seed germination. Conduct a soil test to determine the exact nutrient deficiencies and soil pH, which should ideally be between 6.0 and 7.0 for optimal turf health.
Mowing height is another adjustable factor that significantly influences clover recurrence. Clover prefers a short canopy, so raising the mower deck to at least three inches encourages the grass to grow taller and deeper roots. Taller grass casts more shade on the soil, making it difficult for low-growing clover to establish. Adopt a deep and infrequent watering schedule to encourage a strong, deep root system.