Grass is more than a ground cover; it is a vital component of your lawn's ecosystem. The establishment of a healthy turf promotes water retention and the preservation of soil nutrients and beneficial organisms. Because there are several types of grasses, each adapted to a specific environment, it's important to select a type that is well-suited to your climate.
Grass Climate Zones
Unlike the U.S. Department of Agriculture's plant hardiness zones, which are based on low temperature tolerance, grass climate zones are based on the season of active growth and are largely defined as either cool- or warm-season. These zones are further categorized by the degree of humidity, resulting in four primary climate zones: cool/humid, warm/humid, cool/arid and warm/arid. In addition, there is a transition zone that extends through the central United States and accounts for temperature and humidity conditions in the region that overlap with each of the other zones. While any type of grass may survive in any of these zones, it is more likely to thrive given the best conditions for its type.
Fescues (Festuca spp.) prefer the cool/humid zone, which corresponds to USDA zones 3 through 7 and includes portions of the Pacific Northwest and Midwest, as well as the Northeast. Red fescue (Festuca rubra), for example, is a low-maintenance grass that prefers shade and requires minimal watering but doesn't like high traffic or heat. Tall fescue (Festuca arundinacea) is a medium-to-dark green lawn turf that performs well in sun or shade. It's also more tolerant of traffic, heat and drought, and resists disease and weeds. Because this grass has a bunch-type growth habit, however, bare areas may occur that will need reseeding.
Kentucky bluegrass (Poa pratensis) is a cool-season grass adapted to USDA zones 2 through 6. This dark green grass produces a thick turf in full sun or partial shade and, because it spreads via underground rhizomes and tillers, it quickly recovers from damage or wear. To enhance resilience and disease resistance, Kentucky bluegrass seed is often applied as a mixture that contains 15 percent perennial ryegrass seed (Lolium perenne), which is suited to USDA zones 3 through 9.
Zoysiagrass (Zoysia spp.) is a warm/humid grass that is also suited to locations within the transition zone, which includes the lower portion of the eastern and central states and USDA zones 5 through 10. It takes time to establish but forms a dense turf that is drought- and pest-resistant and tolerant of heavy traffic. Frequent mowing and the periodic use of a thatching rake or vertical mower is necessary to prevent excessive thatch. Japanese lawn grass (Zoysia japonica) is a good choice for cooler climates in USDA zones 6 through 9.