When selecting turfgrasses to establish a lawn, consider species that will be best adapted to your environmental conditions, intended use and the maintenance level at that particular site. Grasses vary in tolerance of soil moisture, pH, fertility and temperature ranges. They also vary in resistance to stresses caused by excessive wear, mowing, insects and diseases. In the Northeast, many species of cool-season grasses (characterized by maximum growth in the spring and fall and semi-dormant during hot and/or dry periods of summer) can be used alone or in mixtures to produce a dense lawn. The principal species of cool-season grasses for lawns are: Kentucky bluegrass, perennial ryegrass, tall fescue and fine fescues (creeping red, Chewings and hard). Creeping bentgrass is a cool-season grass used for very closely-mown, high-maintenance playing surfaces such as putting greens or croquet courts. It is not an appropriate lawn grass. Cultivars within each species offer further options of improved aesthetic and resistance qualities.

Certain cultivars of perennial ryegrass, tall fescue and fine fescues also contain fungal endophytes. A fungus living inside these grasses enhances the qualities of the turf, but is not visible on the grass surface. Endophytic grasses have a high tolerance for environmental stresses and may perform well under low-maintenance regimes. Endophytic grasses also have resistance to leaf-feeding insects such as billbugs, sod webworms and chinch bugs. Fine fescues containing these endophytes also resist dollar spot, a disease associated with low fertility.

Kentucky Bluegrass:

Kentucky bluegrass has fine to medium leaf texture and is dark green in color. It spreads via rhizomes (underground stems), allowing for good sod-forming abilities. Tolerance is high for cold temperatures and wear, and moderate for heat and drought. The grass becomes semi-dormant under hot and dry conditions. It will recover quickly in cooler temperatures and with adequate moisture. Kentucky bluegrass is best grown in well-drained, sunny areas, although a few cultivars tolerate some shade (e.g. 'Glade' and 'A-34'). It requires higher amounts of N fertilizer (2-3 lb. N/1000 sq.ft. per growing season) than some other cool-season grasses and may produce a significant amount of thatch if over-fertilized or over-watered. Kentucky bluegrass may be susceptible to such diseases as leaf spot, dollar spot, stripe smut, necrotic ring spot and summer patch. Some newer cultivars show some disease resistance.

Perennial Ryegrass:

Perennial ryegrass has a fine to medium leaf texture and tends to be dark green. It germinates rapidly and is quick to establish, making it suitable for overseeding. It is competitive with other grasses, however, and is used either alone or in combinations with Kentucky bluegrass or fine fescues. Use no more than 20% perennial ryegrass when mixing with other grass species. It is wear- and heat-tolerant, but will not withstand shade and drought well. It is susceptible to ice cover injury, although some cultivars recover from this damage better than others. Perennial ryegrass does best on well-drained soils with moderate fertility. The nitrogen requirement for perennial ryegrass is approximately 2 - 3 lb. N/ 1000 sq. ft. per season with little thatch accumulation. Perennial ryegrass is most susceptible to diseases such as brown patch, Pythium blight, dollar spot, red thread and rust. Several cultivars of perennial ryegrass contain beneficial fungal endophytes, which provide some insect resistance.

Tall Fescues:

Many new, finer textured, darker green "turf-type" varieties now make tall fescue an option for lawns. Tall fescue is slow to establish, preferring temperatures above 70 degrees F for optimal germination. It has only a fair recovery potential, but it is both heat and drought tolerant. Tall fescue performs best in well-drained soils in open, sunny areas but can withstand moderate shade. Overall, it is more shade tolerant than Kentucky bluegrass and perennial ryegrass, but less so than the fine fescues. Tall fescues require 2.5-3 lb. N/1000 sq. ft per growing sea-son with minimal accumulation of thatch. Most cultivars should not be mown at less than 2 inches. Tall fescue is highly susceptible to brown patch, red thread and Pythium blight.

Fine Fescues:

Creeping Red Fescue
Chewings Fescue
Hard Fescue

These narrow-leaved, medium-green to dark green grasses can be used either alone or in combination with other grasses. Each species varies somewhat in terms of growth characteristics, but all are ideal for low-maintenance situations. They are very tolerant of low pH and fertility, and of drought and shade. Fine fescues do not perform well under hot, humid conditions or with high levels of fertility. Fine fescues become semi-dormant in heat and drought, but recover quickly. These grasses require 1-2 lb. N/ 1000 sq. ft. per growing season with minimal production of thatch. Fine fescues are susceptible to leaf spot, red thread and dollar spot. Endophytes containing cultivars have dollar spot and some insect resistance.

Mixes and Blends:

A grass seed mix is made up of two or more different species of grasses. A typical home lawn seed mix, for example, may be made up of varieties of Kentucky bluegrass, perennial ryegrass and fine fescues. A mix of these species is generally fairly adaptable to differing site conditions (shade, full sun, dry, moist). Most lawns should be made up of a mixture of grasses appropriate for the particular site. A blend is made up of two or more cultivars or varieties of the same species of grass. For instance, a blend of perennial ryegrass might be made up of three or more varieties of perennial ryegrass. Blends are often used in highly-maintained lawns where extremely uniform appearance and performance are required, or for overseeding established lawns or play areas. For either blends or mixes, include at least three cultivars or varieties.

Specialty Grasses:

Several other cool-season grasses can be used for special situations. These include:

Rough bluegrass, Poa trivialis:
This light green grass is shade-tolerant. It requires moist, fertile soils, with some shade preferred. It is an aggressive grass but will not tolerate heat, drought or traffic. Rough bluegrass requires approxi-mately 2 to 3 lb. N/1000 sq. ft. per season. Because it spreads by stolons (aboveground stems), it does not mix well with other species. Cultivar choices are limited.

Alkaligrass:
Alkaligrass is suited for high pH or salty soils. This dark-green, medium to fine-textured, cool-season grass is good for use along road-sides and in areas near the coast which are subjected to annual salt spray. Alkaligrass tolerates regular mowing, but also maintains an excellent aesthetic value in unmown situations. A few cultivars are available of this species.

Supina bluegrass, Poa supina:
This is a relatively high-maintenance, aggressive and vigorously growing grass. It is typically light green and spreads via aboveground stems (stolons). Supina bluegrass is being used and evaluated under very high-traffic situations such as athletic fields. Very limited cultivars are available.

Bentgrasses:
Bentgrasses, including creeping bentgrass, are typically grown under low-mown (less than 1/2 inch), high-maintenance situations. They are the grasses of choice for putting greens, bowling greens and croquet courts. They become a weed in a higher-mown lawn situation, forming "puffy" circles of grass. Bentgrasses are prone to scalping.

Suggested Cultivars for Rhode Island:

Kentucky Bluegrass: 'Georgetown' (developed at URI), 'Award,' 'Midnight,' 'Blackstone,' 'Glade'

Perennial Ryegrass: 'Palmer III,' 'Calypso II,' 'Secretariat,' 'Panther,' 'Brightstar'

Fine Fescues:

Creeping Red Fescue: 'Florentine,' 'Shademaster II'
Chewings Fescue (These cultivars do well in mixes with Kentucky Bluegrass): 'Jamestown II' (developed at URI), 'Brittany,' 'Tiffany'
Hard Fescue: 'Reliant II,' 'Defiant'

Adapted from the University of Massachusetts Extension, 1999