Turf grasses are the flat-bladed plants of several different species that homeowners as well as recreational field managers plant at dense seed spacings to create lush lawns, ball fields, parks and golf courses. Turf grass species and cultivars within those species vary in their tolerance of heat, cold, sunlight and shade, and wet or dry soils. Selecting the right turf grass type for your growing conditions goes a long way toward ensuring a green, healthy lawn.
Cool-season turf grasses are those species and cultivars that can tolerate cooler summer seasons and survive potentially harsh winters. The United States National Arboretum advises that cool-season turf grasses thrive in temperatures between 65 and 75 degrees F. Cool-season grasses can be grown in most of the United States north of Virginia and Oklahoma and at higher elevations in more southerly locations. The Purdue University Extension lists Kentucky bluegrass, perennial ryegrass, tall fescue, fine fescue and creeping bentgrass as successful cool-season grass species. The Virginia Extension advises that many fine fescue cultivars such as creeping red fescue, hard fescue and chewings fescue are also shade-tolerant in most cool-season regions.
The University of California at Davis Integrated Pest Management Program advises selecting warm-season turf grass species for areas with hot summers to minimize insect and disease damage to your lawn. According to the National Arboretum, warm-season grasses grow best at temperatures between 80 and 95 degrees F and thrive in the most southerly regions of the United States. Recommended species include Bermudagrass, buffalograss, kikuyugrass, St. Augustine and zoysia. These species will all turn uniformly brown if temperatures drop close to freezing, but will withstand scorching summer heat and dry conditions, remaining green through the hottest summer months.
Mixes and Blends
The Purdue University Extension advises that turf grass blends--a combination of two to four cultivars within one turf grass species--are beneficial for most home and recreation growing conditions because different cultivars have varying tolerance for soil moisture levels and sunlight and shade conditions. A blend of cultivars will create a uniform lawn appearance while allowing each cultivar to dominate the growth in the areas in which it best thrives. Mixtures of two or more turf grass species are recommended for a transition zone, which the National Arboretum defines as the region from southern New Jersey south to the Carolinas and west to Arizona and Colorado, where spring and fall can be cool but midsummer still brings searing heat. In these areas, combining several species of turf grass can create a better chance of having a green lawn all through the growing season. The Virginia Cooperative Extension recommends a mixture of perennial ryegrass and Kentucky bluegrass for transition zones, particularly for higher elevations.