Zoysia grass is a popular warm-season turf, widely recognized for its high tolerance to drought and heat. This makes it a preferred choice in the southern and transition zones of the United States. Zoysia has evolved specific mechanisms that allow it to remain vibrant during short periods of dryness and survive extended periods without rainfall. Its natural resilience means homeowners can maintain a dense, attractive lawn while requiring significantly less water than many other common turf types.
The Biological Basis for Zoysia’s Resilience
The drought tolerance of Zoysia grass is rooted in its unique physical and biological structure. It is characterized by a deep and extensive root system that grows downward, allowing it to access moisture reserves in deeper soil layers unavailable to grasses with shallow roots. This adaptation is valuable during dry spells, helping the plant sustain itself long after surface moisture has evaporated.
Zoysia also utilizes specialized horizontal growth structures called rhizomes and stolons. Rhizomes are underground stems, and stolons creep along the soil surface. Both structures store water and carbohydrates, acting as built-in survival reserves that enable the plant to endure stress.
When severe drought conditions persist, Zoysia employs a defense mechanism by entering a state of controlled dormancy. The grass quickly conserves its internal water supply by shutting down active growth, causing the above-ground foliage to turn a straw-like tan color. This browning is a survival strategy, allowing the plant’s crown and root system to remain alive while waiting for moisture to return.
Managing Zoysia During Dry Periods
Maintaining Zoysia grass during drought stress requires a specific approach to watering and care. Established Zoysia needs about one inch of water per week, either from rainfall or irrigation, to stay actively green. It is most effective to water deeply and infrequently, soaking the soil completely to encourage deep root growth, rather than giving short, daily sprinkles that only wet the surface.
A simple way to determine if the turf needs water is by performing the “footprint test.” If your footprints remain visible for an extended period, the grass blades lack the turgor pressure necessary to spring back, indicating the plant is stressed and requires immediate irrigation. When watering, aim for the early morning hours. This minimizes water loss to evaporation and allows the foliage to dry before nightfall, reducing the risk of fungal disease.
During periods of high heat and low water availability, adjust your mower deck to a higher setting, such as between 1.75 and 2.5 inches. Taller grass blades create more shade for the soil, which helps keep the roots cooler and reduces the rate of water evaporation. It is also important to refrain from applying fertilizer during extreme drought, as stimulating new growth when water resources are limited will only exacerbate the stress on the plant.
Post-Drought Recovery and Long-Term Health
One of Zoysia’s favorable traits is its ability to recover once moisture returns. When a dormant lawn receives sufficient water, it typically begins to green up rapidly, often showing noticeable signs of recovery within seven to 14 days. The underground rhizomes and protected crowns quickly push out new, green shoots, demonstrating the success of the dormancy survival mechanism.
To ensure a swift rebound, hold off on applying fertilizer until the grass shows consistent new growth. Once recovery is underway, a balanced, slow-release fertilizer can be applied to provide the necessary nutrients without causing a sudden surge of growth that could overwhelm the re-establishing root system.
Long-term resilience is enhanced by maintaining good soil health, which includes periodic core aeration to relieve compaction. Aeration creates channels in the soil, allowing water and air to penetrate more easily. This promotes deeper root development and improves the turf’s ability to withstand future dry conditions. A healthy Zoysia lawn builds up the carbohydrate reserves needed for successful dormancy and subsequent recovery.