Zoysia grass is a durable, warm-season turf known for its dense, carpet-like appearance. It creates a thick, cushiony lawn, making it a premium choice for residential yards. Maintaining this density and the grass’s overall health relies heavily on a precise mowing regimen. The cutting height is the most influential factor affecting its appearance, root development, and resilience against stress and disease.
The Standard Recommended Mowing Range
For most residential Zoysia lawns, the ideal cutting height falls within a range of 1 to 2.5 inches. This range represents a balance between achieving the manicured aesthetic that Zoysia offers and ensuring the plant can sustain itself through photosynthesis. Cutting the grass too short removes too much of the photosynthetic surface, starving the plant and inhibiting the deep root growth necessary for drought tolerance. Conversely, allowing the grass to grow beyond the higher end of the range can lead to excessive thatch buildup, which restricts air and water movement to the soil. This thatch layer also raises the plant’s crown too high, making it susceptible to scalping and creating an environment favorable for certain diseases.
Adjusting Height Based on Cultivar and Environmental Stress
Cultivar Considerations
The specific cultivar of Zoysia grass plays a significant role in determining the best height within the standard range. Fine-bladed varieties, such as Zeon, Emerald, or Zorro, are often maintained at the lower end, typically between 1 and 1.5 inches, to achieve a golf course-like finish. These varieties often require a precision reel mower to handle the lower cut cleanly and consistently. Coarser, wider-bladed types, including Meyer or Palisades Zoysia, generally perform better when kept slightly taller, thriving between 1.5 and 2.5 inches.
Managing Environmental Stress
Environmental conditions also dictate a temporary adjustment to the cutting height to reduce stress on the plant. If the lawn is under heavy drought stress or experiencing intense summer heat, raising the mower height to the 2.5-inch mark is beneficial. Taller grass blades provide a greater surface area for photosynthesis, which helps the plant generate more energy to cope with the stress. Furthermore, the increased height shades the soil, lowering the surface temperature and significantly reducing moisture evaporation during dry periods. Zoysia growing in partial shade should also be cut at the higher end of the range to maximize the limited light available for energy production.
The One-Third Rule and Mowing Frequency
The technique of how the grass is cut is equally as important as the final height, governed by the “One-Third Rule.” This principle states that no more than one-third of the total grass blade length should be removed in any single mowing session to prevent undue shock to the plant. For example, if the desired final height is 2 inches, you should mow before the grass reaches approximately 3 inches tall. Violating this rule by cutting the grass too short can lead to a condition known as scalping, which removes the active green tissue and exposes the brown undergrowth and stems. Adhering to the One-Third Rule necessitates frequent mowing, especially during the peak growing season; homeowners should plan to mow weekly, or even every five days, to ensure the grass maintains its energy reserves and promotes a consistently dense, healthy lawn surface.
Seasonal Height Adjustments
The mowing height should be intentionally altered twice a year to help Zoysia grass transition smoothly between seasons. In early spring, just before the grass breaks dormancy, a practice known as “scalping” is performed. This involves briefly lowering the mower to its lowest setting to remove the straw-colored, dormant leaf tissue and any accumulated debris. Scalping allows sunlight to penetrate the canopy, warming the soil more quickly and promoting an earlier, uniform emergence of new growth. Conversely, as the growing season slows down in late fall, the cutting height should be gradually raised by 0.5 to 1 inch above the standard summer height; this final, taller cut provides insulation to the grass crowns and allows the plant to store more carbohydrates for a strong return in the spring.