The increasing frequency of drought conditions and water restrictions has made water-wise landscaping a necessity. Selecting the right turfgrass is the most important decision in creating a lawn that can survive with minimal supplemental water. The “best” drought-tolerant grass is not a single species but the one whose survival strategies and growth habits match your specific climate and site conditions. This article guides you through the science of grass survival and the top contenders for both warm and cool-season regions.
Understanding How Grasses Survive Drought
Turfgrasses employ two primary biological mechanisms to endure periods of dryness: drought avoidance and drought tolerance. Drought avoidance is achieved through the development of deep, extensive root systems that access moisture reserves far below the soil surface. This allows the grass to maintain green tissue and continue growth longer than shallow-rooted varieties by postponing tissue dehydration.
The other strategy is drought tolerance, often expressed as dormancy. During prolonged dry spells, the grass intentionally halts shoot growth and turns brown, conserving water and energy while the crown and root system remain alive. This state of summer dormancy reduces the plant’s metabolic activity and water use, allowing it to survive until rain or irrigation returns and recover fully.
Key Factors in Choosing the Best Grass
Selecting the best grass begins by evaluating the specific conditions of your location. The most important consideration is your geographical climate zone, which determines whether a warm-season or cool-season grass is appropriate. Warm-season grasses thrive in summer heat and go dormant in winter, while cool-season grasses grow best in spring and fall.
Soil type is another determining factor because it dictates water retention and root growth depth. Grasses relying on deep roots, such as Bahia, excel in sandy soils where roots easily penetrate to lower levels. Heavy clay soils, which hold water tightly but compact easily, may require species with strong rhizomes or those that handle poor drainage. Finally, consider the expected traffic, as some drought-tolerant varieties, like certain fescues, do not hold up well to heavy foot traffic under moisture stress.
Warm-Season Grass Recommendations
Warm-season grasses are better equipped for drought survival because they are adapted to endure high heat and prolonged dryness. Bermudagrass (Cynodon dactylon) is a top contender, known for its extensive root system that can reach depths of six feet or more, enabling drought avoidance. It has a rapid growth rate and aggressive spreading mechanism (stolons and rhizomes), giving it excellent recuperative ability after dormancy. Its main drawback is its high demand for full sun and frequent mowing.
Zoysia grass (Zoysia spp.) offers a balance of drought and shade tolerance, making it a good choice for the transition zone and areas with partial sun exposure. It survives drought by entering dormancy that can last up to five weeks, relying on its deep rhizomes for survival and self-repair. However, Zoysia is slow to establish and can produce a heavy layer of thatch that requires occasional dethatching.
For homeowners with sandy or nutrient-poor soil, Bahia grass (Paspalum notatum) is a tough, low-maintenance option. Its deep, strong root system is highly effective at drawing moisture from deep soil layers, requiring less fertilizer and irrigation than Bermuda or Zoysia. The trade-off for this resilience is a coarser texture, a lighter green color, and a tendency to produce frequent seedheads.
Cool-Season Grass Recommendations
Cool-season grasses, standard in northern climates, have a lower tolerance for prolonged heat and drought compared to warm-season counterparts. Tall Fescue (Festuca arundinacea) is the most drought-resilient cool-season option due to its deep-rooting mechanism. Its roots can grow two to three feet deep in favorable soil, allowing it to stay green longer during dry periods. Tall Fescue varieties are also tolerant of wear and offer better shade tolerance.
For areas with significant shade or low-input requirements, Fine Fescues (Festuca spp.), such as Chewings or Creeping Red Fescue, are an excellent choice. These varieties are known for their exceptional shade tolerance and very low water and nutrient requirements. Fine Fescues utilize a tolerance strategy by entering summer dormancy quickly, requiring significantly less water to maintain than Tall Fescue or Kentucky Bluegrass. Their ability to survive depends on their capacity to enter and break dormancy when conditions improve, though they may struggle in prolonged, severe droughts.
Water-Wise Maintenance Practices
The drought resilience of any turfgrass is enhanced by adopting specific, water-wise maintenance practices. Adjusting the mowing height is an effective strategy; keeping the grass taller, typically between three and four inches, shades the soil surface. This increased height helps keep the soil cooler and reduces water loss from evaporation.
The most impactful change is shifting to deep and infrequent watering. Applying water until the soil is moist six to eight inches deep encourages roots to grow downward, maximizing the grass’s natural drought-avoidance mechanism. Watering less often, such as once or twice a week, allows the upper soil layer to dry out partially, training the roots to seek deeper moisture.
Periodic core aeration is beneficial, especially in compacted or heavy clay soils. This process removes small plugs of soil, creating channels that allow water, air, and nutrients to penetrate deep into the root zone. Aeration improves drainage and reduces the risk of runoff, ensuring water reaches the deeper roots.