The ability of turfgrass to maintain function or recover quickly after an extended period without water defines its drought tolerance. As water conservation becomes a greater focus in landscaping and lawn care, selecting grass species with high drought tolerance is a practical way to manage resources. The choice of grass depends heavily on the local climate, as different species employ distinct biological strategies to survive water scarcity.
How Grasses Cope with Water Scarcity
Turfgrasses primarily use two biological strategies to survive periods of prolonged dryness: drought avoidance and drought tolerance. Drought avoidance focuses on maintaining the plant’s internal water content by minimizing water loss or maximizing water uptake. Mechanisms of avoidance include developing deep, extensive root systems that access water reserves deeper in the soil profile.
Avoidance also involves physical adaptations like leaf rolling, which reduces the surface area exposed to the sun and wind, limiting water loss through evapotranspiration. Grasses that employ true drought tolerance can endure a low internal water content by adjusting cellular processes. This often involves the plant entering dormancy, where metabolic activity is shut down and the leaves turn brown to conserve moisture. This strategy allows the plant to “escape” drought conditions and rapidly recover once water becomes available.
Warm-Season Grasses: The Maximum Tolerance Champions
Warm-season grasses, which thrive in high temperatures, typically exhibit the highest level of drought tolerance. These grasses are often used in the southern United States and transition zones where water restrictions are common. Their biological makeup allows them to require significantly less water than their cool-season counterparts.
Buffalo Grass (Bouteloua dactyloides) is often cited as the most drought-tolerant turfgrass available due to its extremely low water needs. This native prairie grass can maintain optimal growth with as little as 0.25 inches of water per week, thanks to its deep root system and ability to go dormant quickly. Buffalo grass is best suited for dry climates with less than 30 inches of annual rainfall, making it an excellent choice for xeriscaping.
Bermuda Grass (Cynodon spp.) is another highly drought-tolerant variety that utilizes a deep, robust root system to access subterranean moisture, classifying it as a drought avoider. It is known for its fast spreading and quick recovery from stress, thriving in full sun and intense heat. Although Bermuda grass may enter dormancy faster than Buffalo grass during a drought, it requires less water than many other turf varieties to survive.
Zoysia Grass (Zoysia spp.) offers excellent drought resilience, with some varieties comparable in tolerance to Buffalo and Bermuda grasses. Zoysia forms a dense, thick sod that helps suppress weeds and reduce surface evaporation. It possesses an extensive root system, allowing it to recover quickly from drought-induced dormancy.
Cool-Season Alternatives for Drier Climates
For regions where warm-season grasses cannot survive cold winters, cool-season varieties offer alternatives with varying degrees of drought resilience. These grasses are generally more water-intensive than warm-season types but are more durable than traditional varieties like Kentucky Bluegrass. Their peak growth occurs during the cooler months of spring and fall.
Tall Fescue (Festuca arundinacea) is considered the most drought-tolerant cool-season turfgrass due to its thick, deep root system, which can grow two to three feet deep. This extensive root structure allows the plant to reach deeper moisture reserves, making it a strong drought avoider. Modern turf-type Tall Fescue cultivars have improved heat tolerance and disease resistance, making them a popular choice for the transition zone.
Fine Fescues (Festuca spp.) are highly resilient, particularly in low-fertility soils and partially shaded areas. They can flourish with minimal watering and often remain green for extended periods in dry conditions.
Types of Fine Fescues
- Creeping Red Fescue
- Chewings Fescue
- Hard Fescue
- Sheep Fescue, which is noted as the most drought-tolerant among the group.
Water-Wise Practices for Long-Term Survival
Selecting a drought-tolerant grass requires proper maintenance practices to maximize water conservation and survival. One effective strategy is adjusting the mowing height, keeping the grass taller than typical. Mowing at the upper end of the recommended height range, such as 3 inches or more, encourages deeper root development. Taller grass blades also shade the soil surface, which reduces water evaporation.
Irrigation should follow a “deep and infrequent” schedule, which trains the root system to grow downward in search of water. Apply enough water to moisten the soil to a depth of four to six inches, typically about one inch per application. Allowing the turf to show initial signs of drought stress—such as a dull blue-green color or footprints remaining—before watering further stimulates deep root growth.
Soil preparation and aeration are also important for improving water infiltration and root health. Core aeration, done in the spring or fall, alleviates soil compaction, allowing water and air to penetrate the root zone more easily. For new installations, tilling the area to a depth of six to twelve inches helps prepare the groundwork for a healthy, deep-rooted stand of turfgrass.