Zoysia grass is a popular warm-season turf known for its dense growth habit, fine texture, and tolerance to drought and heat. While resilient, this grass can sustain damage from environmental factors, physical stressors, or biological threats. Repairing Zoysia requires specific methods because its lateral growth via stolons and rhizomes is slower than other turf varieties, meaning damaged areas will not fill in quickly without intervention.
Diagnosing Common Zoysia Damage
Repairing your Zoysia lawn begins with accurately identifying the root cause of the damage. A visual inspection helps differentiate between issues requiring cultural changes and those needing targeted treatments. Look closely at the pattern and color of the distressed areas to narrow down the possibilities.
Physical and environmental factors often result in uneven thinning or browning. Heavy foot traffic leads to wear patterns or soil compaction, starving the roots of oxygen and water. Drought stress causes blades to turn a dark, bluish-gray color before wilting, while insufficient sunlight causes the turf to thin out gradually in shaded areas.
Biological issues like disease and pests present with distinct patterns. The most prevalent fungal problem is Large Patch, which appears as circular, sunken patches of light brown grass often surrounded by a yellowish-orange border. Pests like grubs feed on the roots, causing irregular patches that can be easily pulled back like a loose carpet.
Repairing Bare Patches and Thin Spots
Once the underlying cause of the turf loss is addressed, focus on physically restoring the turf layer in bare or severely thinned areas. Due to Zoysia’s slow spread, the most effective repair methods involve introducing new, mature grass material rather than relying solely on seeding. This provides an immediate fix and reduces the opportunity for weeds to colonize the empty soil.
The most common method is plugging, which involves planting small pieces of Zoysia sod into the damaged area. You can harvest these plugs from a healthy part of your lawn or purchase them commercially, spacing them six to twelve inches apart. When planting, ensure the top of the plug is level with the surrounding soil to encourage lateral spread via its runners.
For larger bare areas, sodding is the quickest repair option. Cut a piece of Zoysia sod to fit the patch exactly, ensuring the soil underneath is tilled and amended for good root contact. Overseeding is challenging because the seed requires specific soil temperatures and continuous moisture to germinate successfully. If seeding is chosen, rake the soil to ensure good seed-to-soil contact and apply a thin layer of compost to help retain moisture.
Restoring Health After Disease or Pest Infestation
Repairing Zoysia after a biological attack requires specific treatment protocols to eliminate the threat and encourage recovery. Fungal diseases like Large Patch thrive in cool, wet conditions, particularly during the transition seasons of spring and fall. Applying a targeted fungicide, such as those containing azoxystrobin or propiconazole, halts the disease’s spread.
Preventative fungicide applications in the fall, often in October, are more effective than curative applications after the patches appear. After treating the fungus, address soil compaction and excessive thatch, which create the humid conditions fungi prefer. Aeration relieves compaction by creating small holes that improve air and water flow to the root zone.
If the damage is caused by pests like white grubs, a targeted insecticide application is required. Grubs are best treated when they are small and actively feeding, usually in mid-to-late summer, using a product that is watered in immediately after application. Addressing underlying issues like excessive soil moisture or high nitrogen levels in the fall helps create an environment less favorable to pests and disease.
Long-Term Recovery and Maintenance
Supporting the repaired Zoysia lawn with appropriate cultural practices prevents future damage and ensures a complete recovery. Zoysia requires a lower nitrogen input than other warm-season grasses, usually between two and four pounds of actual nitrogen per 1,000 square feet annually. During recovery, use a slow-release fertilizer formulation to provide a steady supply of nutrients without promoting excessive growth that could attract disease.
Proper mowing supports the grass’s health and density. Zoysia should be maintained at a height of one to two inches, depending on the specific cultivar. Always adhere to the one-third rule, removing no more than one-third of the blade height during any single mowing session to avoid stressing the plant.
Watering should be deep and infrequent to encourage the development of a robust root system. Zoysia needs about one inch of water per week, either from rainfall or irrigation. Watering in the early morning allows the leaf blades to dry completely before nightfall, which reduces the humidity that promotes fungal growth.