Turfgrasses are typically used for lawns, sports turf fields, and golf courses, but can be planted for a wide range of applications that provide a few basic needs; soil stabilization, cushion, and aesthetics. Although there are many species and varieties available to choose from, there are basically two types of turfgrasses: cool-season and warm season. This simple categorization describes the climate and geographical region where the grass performs best. In recent years another type has been termed, the "transition zone grass". Transition zone grasses can be either warm-season or cool-season. This "transition zone" refers to a narrow band running east to west across the central region of the United States. This zone is a transitional area that is not especially suited for either type of grass but some species and varieties perform better than others. It tends to be the most difficult geographic region to manage grass since temperatures fluctuate to the extremes.
Cool-season grasses perform best in the northern regions of the United States where there are cold winters and warm summers. Although they perform best in the north, many are planted in the southern regions to take advantage of the shade tolerance and year-round-green characteristic which is lacking in nearly all warm-season grasses. New cool-season grass varieties have improved drought tolerance, heat tolerance, and disease tolerance, but still struggle in southern regions without intensive management. Grass species such as tall fescue, annual ryegrass, perennial ryegrass, bluegrass, and creeping bentgrass are the most common. These species are also often blended to take advantage of their complementing characteristics.
Warm-season grasses perform best in the southern region of the United States where there are relatively mild winters and hot summers. Warm-season grasses are moving further north into cool-season regions, especially the new seeded bermudagrasses like Riviera with improved cold tolerance. Buffalograss is also unique since it has high a degree of cold tolerance. Warm-season grasses are generally drought tolerant, heat tolerant, and disease resistant but typically have low levels of cold tolerance and shade tolerance. The most common warm-season turfgrasses are bermudagrass, buffalograss, zoysiagrass, St. Augustine grass, and centipedegrass. Warm-season grasses are rarely blended due to contrasting growth habits and management requirements.
Transition Zone Grasses
The transition zone presents a unique set of climatic problems that test species and varieties to the limit. In recent years, grasses have been specifically developed to handle these extremes of heat and cold. Riviera seeded bermudagrass, released by Oklahoma State University with funding from the United States Golf Association , is a grass variety developed specifically for improved performance in this region. Buffalograss also does well in this region but it typically is not thought of as a high-performance turf for sportsturf and golf applications. Tall fescues perform adequately with supplemental watering and annual over seeding.