Kikuyu grass (Pennisetum clandestinum) is a warm-season perennial turf highly valued for its exceptional resilience and aggressive growth habit. Originating in East Africa, this species develops a dense turf using above-ground runners (stolons) and below-ground stems (rhizomes). This robust structure allows the grass to withstand heavy foot traffic, tolerate drought, and rapidly recover from injury, making it a popular choice for sports fields and home lawns. Despite its hardiness, its vigorous nature requires specific management solutions to maintain a healthy appearance.
Dealing with Common Weed Infestations
The aggressive growth of Kikuyu grass naturally suppresses many weeds, but persistent types still manage to invade and compete for resources. Weeds fall into two categories: broadleaf and grassy weeds, each requiring a different control strategy. Broadleaf invaders, such as clover, bindii, and wood sorrel (Oxalis), are often controlled using selective herbicides containing active ingredients like MCPA or 2,4-D. These chemicals target the broad, non-grass foliage without harming the Kikuyu turf.
Grassy weeds like crabgrass (Digitaria sanguinalis) and annual wintergrass (Poa annua) pose a greater challenge because they are botanically similar to Kikuyu grass. Selective post-emergent herbicides that kill these grassy weeds can often damage the desirable turf, requiring careful product selection and application. A more effective preventative measure involves using pre-emergent herbicides in early spring or autumn to stop weed seeds from germinating. Physical removal by hand is generally inefficient for all but the smallest infestations due to the deep root system of Kikuyu and the spreading nature of many weeds.
Identifying and Treating Insect Pests
Several insect pests target Kikuyu grass, and identifying the specific culprit based on damage symptoms is the first step toward successful treatment. One destructive pest is the lawn grub, which includes the larvae of beetles such as the African black beetle and billbugs. These grubs feed on the root system just below the soil surface, causing the grass to yellow, wilt, and die in irregular, straw-like patches. These damaged areas can often be peeled back like a loose carpet.
Above-ground pests like armyworms and sod webworms are the larval stage of moths that feed voraciously on the grass blades, typically at night. A severe armyworm infestation can defoliate large sections of the lawn rapidly, resulting in thinning patches and a “chewed” appearance. Control methods often involve applying targeted insecticides containing ingredients like chlorantraniliprole, which offers both curative and preventative action against grubs and surface-feeding caterpillars. Biological controls, such as beneficial nematodes, can also be introduced to the soil to suppress grub populations.
Managing Fungal Diseases
Kikuyu grass is susceptible to several fungal diseases, especially when conditions are warm, humid, and the turf is stressed by improper cultural practices. Brown Patch, caused by Rhizoctonia solani, appears as large, circular areas of brown or dead grass, often with a darker, smoke-ring border during high humidity. Dollar Spot presents as smaller, silver-dollar-sized patches that are tan or straw-colored.
A specific issue is Kikuyu Yellows, a root rot caused by Verrucalvus flavofaciens, which results in distinct yellowing patches that can eventually die out. Altering maintenance practices is the most effective defense against most fungal problems, as prolonged leaf wetness promotes fungal growth. This involves switching to deep, infrequent watering cycles and avoiding late afternoon or evening irrigation to ensure the grass blades dry completely before nightfall. While fungicides like Mancozeb or Daconil can be used for acute infections, improving soil drainage and aeration is the long-term solution, particularly for root-based diseases like Kikuyu Yellows, which lack readily available home-use fungicides.
Correcting Cultural and Environmental Stressors
Cultural practices profoundly impact the overall health of Kikuyu grass, and correcting maintenance errors prevents many pest and disease problems. Since Kikuyu grows aggressively, it produces a significant amount of thatch—a dense layer of organic material between the soil surface and the green grass blades—which must be managed. Excessive thatch harbors pests and diseases and can be reduced through annual dethatching or verticutting during the peak growing season.
Mowing Height and Frequency
Improper mowing is a frequent stressor, particularly mowing too low, which is known as scalping. Kikuyu grass should be maintained at a height between 2 and 3 inches. To prevent stress, no more than one-third of the blade height should be removed in a single mowing session. This practice encourages deeper root growth and prevents the grass from becoming vulnerable.
Fertilization Needs
Kikuyu grass is a heavy feeder that responds positively to nitrogen fertilizer. It often requires an annual application of 2 to 3 pounds of nitrogen per 1,000 square feet. This supports its rapid growth and helps maintain its vibrant color.