Turf grasses can be divided into two groups, cool-season grasses and warm-season grasses. Cool-season grasses flourish in spring and fall and go dormant in the worst heat of summer and the coldest part of winter. They usually remain some shade of green through both dormant periods. Warm-season grasses thrive on heat, but go dormant when temperatures drop. Most warm-season grasses turn brown when they enter fall dormancy, and remain so until the following spring. Within these broad classifications there are several species of turf grass.
Kentucky bluegrass is the most widely planted lawn grass in the United States. It is a cool-season grass that produces a medium-fine textured turf, with a blue-green hue. It is best adapted to the Northern states east of the Rockies and the Pacific Northwest. It requires careful nurturing in the "transition zone"---an area extending from southern New Jersey south to South Carolina and west to include the panhandles of both Texas and Oklahoma and virtually all of Kansas.
The transition zone is that part of the country too cool for warm-season grasses to be the standard, and too hot for cool-season grasses to look good in mid-summer. Both warm-season and cool-season types have one or two species that work in the transition zone. If you're in the northern part of the transition zone, Kentucky bluegrass may be used in your area, but it will need irrigation and careful mowing.
Fine fescue produces a very fine-bladed turf. It germinates and establishes quickly and tolerates shade better than many other cool-season grasses. Like Kentucky bluegrass, there are better choices for the transition zone, but it thrives in the Northern states east of the Rockies and in the Pacific Northwest. Fine fescue loses its color quickly in extended hot, dry spells.
This is the cool-season grass best adapted to the transition zone. It has a coarser blade texture than Kentucky bluegrass or fine fescue. It displays a clumping habit in thin, poorly maintained turf. It handles heat better than any other cool-season grass. It survives winter best in areas where cold temperatures don't go too low or stay too long.
This is the most wear-tolerant of all cool-season grasses. It forms a deep green, glossy turf with a fine texture. However, it tolerates neither extremes of heat or cold. It is best adapted to coastal environments where extremes are uncommon.
Zoysia is the most cold tolerant of the warm-season grasses, making it a viable choice for the transition zone. Several strains are available, some bred to offer earlier green-up and later dormancy. Zoysia produces a relatively fine-bladed turf. Its habit of growing with surface runners creates a carpet-like feel to the lawn, but also makes it prone to thatch build-up. Frequent core aeration will help control thatch. It prefers to be cut short, two inches or under.
Bermuda is the most commonly planted warm-season grass. It does best in warm climates and is used as far north as some southern sections of the transition zone. Its ability to stand up to heavy traffic makes it the preferred choice for parks and athletic fields in the South. Like zoysia, Bermuda likes to be cut short, but if you're planning to keep it around one inch, realize that it will require mowing twice weekly to keep it attractive and healthy.
St. Augustine is the turf grass most favored along the Gulf coast. It cannot survive much further north than that. It has a coarser blade than either Bermuda or zoysia and a growth habit that prefers to be cut at around three inches.