Grasses belong to one of the most evolutionarily advanced families of plants called Poaceae. The Poaceae family is subdivided into six subfamilies that include 25 tribes, 600 genera and 7,500 species. Nevertheless, only a few dozen species are suitable as turfgrasses because they must form uniform soil coverage and tolerate mowing and traffic associated with turf use. One key characteristic of these grasses that makes them suitable as turfgrasses is their compressed crown. This enables you to mow without cutting off the growing point and killing the plant. See “Taxonomy of turfgrasses” (page 20) for a list of grasses suitable for turf.
Of the three subfamilies that turfgrasses fall into, the Festucoideae subfamily is comprised of cool-season turfgrasses, and Panicoideae and Eragrostoideae include the warm-season turfgrasses. Differences in temperature-related turfgrass physiology, discussed in Chapter 1, primarily influence adaptation of the turfgrasses. Warm-season turfgrasses are best adapted to southern climates, and cool-season turfgrasses are best adapted to northern conditions (see Figure 1, below). Drought tolerance and avoidance also influence adaptation on non-irrigated sites. Because of these differences in adaptation, no one turfgrass species will perform well in all locations. You must consider which species and cultivars are best for your particular location. Your local cooperative-extension service can supply you with a list of turfgrasses that are best adapted to your site conditions. Seed suppliers also can assist you in determining the best turfgrasses for your site.
Fescues. Fescues can be broadly divided by their leaf texture: fine-leaved fescues (creeping red fescue, sheep fescue, Chewings fescue and hard fescue) and tall fescue. Fine-leaved fescues are best adapted to well-drained, low-fertility, low-pH soil and shade. They do not take heat very well and do best when not overfertilized. You will see fine-leaved fescues in mixes with Kentucky bluegrass and perennial ryegrass in cooler climates and in mixes with perennial ryegrass for winter overseeding of warm-season turfgrasses. Of the fine-leaved fescues, only creeping red fescue is rhizomatous. The rest are bunch grasses.
Tall fescue is a relatively coarse-leaved, bunch-type turfgrass that is best adapted to the transitional climatic zone between North and South. Tall fescue is adapted to a wide range of soil conditions and, among cool-season species, tolerates heat and drought well. Because of its coarse-leaf texture, it is best planted alone without being mixed with other more narrow-leaved species.
Bluegrasses. Kentucky bluegrass is the most widely used turfgrass in cool, temperate regions. Its medium leaf texture and dark color make it an attractive turf for lawns. It is rhizomatous, a good sod-former and recuperates well from injury. Kentucky bluegrass responds well to fertilization and will persist in transitional areas when irrigated. One concern of Kentucky bluegrass is its susceptibility to summer patch, a lethal disease that is difficult to control. Some cultivars are more resistant to summer patch than others. More than 100 cultivars of Kentucky bluegrass are available to consumers. These cultivars can differ dramatically in color, disease tolerance, fertility requirement and shade tolerance. Because of this variability, it is extremely important to obtain local recommendations for the best cultivars for your site.
Annual bluegrass is a light apple-green-colored bluegrass that seeds profusely at very low mowing heights. Primarily a bunch-type winter annual (one type is weakly stoloniferous and is more perennial), it tolerates low mowing and can quickly invade bentgrass greens. Because of its light-green color and the seed heads it produces, it can be a serious weed in bentgrass greens. Annual bluegrass is generally not planted intentionally but will naturally invade well-watered sites. It does not tolerate drought and is prone to many diseases. Because of its pernicious nature, turf managers often give up on keeping it out of turf and end up managing it as a desirable species. Turfgrass breeders currently are developing commercially viable annual-bluegrass varieties.
Rough bluegrass is another light apple-green-colored bluegrass. It is stoloniferous and well adapted to damp, fertile, shaded sites. Rough bluegrass has poor heat and drought tolerance. Because of its stoloniferous growth habit, it tends to segregate itself in patches if mixed with Kentucky bluegrass. Rough bluegrass tolerates cold temperatures well and is used as an overseeded species in warm-season turfgrass stands.
Ryegrasses. Both perennial and annual ryegrasses are available for turf. Perennial ryegrass is a medium- textured turfgrass adapted to moderate temperatures. It germinates quickly (within a week) and is most commonly used as a nurse grass in mixes with slower growing species such as Kentucky bluegrass and for winter-overseeding in warm-season species. It has good wear resistance, and, coupled with quick germination, it makes a good species for athletic-field turf mixes. One lethal disease that perennial ryegrass is particularly susceptible to is Pythium blight.
Annual ryegrass is a cool-season, annual bunch grass with coarse-textured leaves. Although it germinates quickly and its seed is inexpensive, it does not persist.
Bentgrasses. Creeping bentgrass is a fine-textured stoloniferous turfgrass that tolerates low mowing heights. Its aggressive stoloniferous growth habit provides it with excellent recuperative potential but also makes it unsuitable in mixtures with other species. Creeping bentgrass requires a high level of maintenance (fertility, mowing and disease control) to maintain it as a lawn. It is most used on golf-course greens, tees and fairways as well as tennis courts and bowling greens.
Colonial bentgrass is fine-textured and sometimes has weak rhizomes and stolons. It can’t be mowed as short as creeping bentgrass but is suitable for fairway turf. Like creeping bentgrass, colonial bentgrass requires a high level of maintenance. Its poor heat tolerance limits its use to cooler, maritime climates.
Velvet bentgrass is the finest-textured turfgrass we use. It is stoloniferous and lighter green in color and is especially tolerant of shade and acidic soil. Because it has poor tolerance of heat and drought, it is only found in cooler maritime climates of the Northeast and Northwest.
Redtop is a coarse-textured, rhizomatous bentgrass that was once used extensively in seed mixtures because of its rapid establishment rate. Unfortunately, redtop persists in newly established turf and, because of its coarse texture, it is not compatible with fine- or medium-textured turfgrasses. Although not used for fine-turf areas, it is still used in some roadside utility mixes.
Bermudagrasses. Bermudagrass is the most important and widely adapted warm-season turfgrass. It is a highly variable turfgrass that produces aggressive rhizomes and stolons. Although primarily propagated vegetatively, improved seeded varieties are becoming available. Bermudagrass thrives in warm, tropical and subtropical climates with moderate to heavy rainfall. Salt tolerance is high. Hybrids developed from crosses between C. dactylon and C. transvaalensis for golf-course use include Tifgreen, Tifdwarf and Tifway, and for home lawns, Midiron, in areas that previously have been too cold for bermudagrass adaptation.
Buffalograss. Buffalograss is one of the few turfgrasses native to the United Sates. Also unique about buffalograss among the turfgrasses is the fact that it has separate male and female plants. Buffalograss is a fine-textured, light green, stoloniferous grass that is well-adapted to unirrigated sites with low fertility.
Zoysiagrasses. Zoysiagrass is a stoloniferous and rhizomatous species used for lawns and golf-course fairways in the South and the transition zone. It is not as aggressive as bermudagrass but forms a dense turf that is prone to thatch buildup. Zoysiagrass withstands cold temperatures better than other warm-season turfgrasses. Japanese lawngrass, a medium-textured turfgrass, is the most cold-tolerant zoysiagrass but, like all warm-season turfgrasses, greens up relatively late in the spring and goes dormant earlier in the fall than cool-season species. Manilagrass is finer-textured but lacks the cold tolerance exhibited by Japanese lawngrass.
St. Augustinegrass. St. Augustinegrass is a coarse-textured, stoloniferous grass that is commonly used for lawns in coastal areas of the deep South. It has poor cold tolerance but tolerates moderate shade better than most warm-season turfgrasses. Salt tolerance is good with St. Augustinegrass, but it does not tolerate traffic or compacted soil. Vegetative propagation is the only means of establishing this species.
Several diseases are a problem with St. Augustinegrass. Perhaps the most serious problems are with brown patch, take-all patch and gray leaf spot. St. Augustine decline virus is another serious problem of St. Augustinegrass with no chemical controls available. Resistant varieties include Floratam, Seville and Raleigh.
Paspalums. Bahiagrass is coarse-textured and has short, almost woody rhizomes and stolons. It’s propagated from seed or sod and is primarily used as a utility grass on highway roadsides and low-maintenance lawns. It performs relatively well in poorly drained, low-fertility soils. Mole crickets are a serious problem in bahiagrass. Seashore paspalum is another species within the Paspalum genus. Its primary use is for its high salt tolerance.
Carpetgrass. Carpetgrass is a coarse-textured, low-growing, stoloniferous grass that forms a dense turf capable of crowding out other species. This species is native to the Gulf states and is adapted to other tropical areas. It’s primarily used on roadsides, airports, golf-course roughs and other utility-turf areas. Its frequent and prolonged production of seedheads is aesthetically objectionable and restricts its use to utility turf.
Centipedegrass. Centipedegrass is a coarse-textured, slow-growing, stoloniferous species. It is established from sod, sprigs and seeding. It is a true low-maintenance turfgrass. Because of its slow growth, it requires less mowing than bermudagrass or St. Augustinegrass. It also performs well with only one annual application of nitrogen at 1 pound per 1,000 square feet. Traffic tolerance is poor, and it is unsuitable as an athletic-field turf. Centipedegrass typically has a natural yellow-green color and is used as a lawn and utility turf.