Choosing Turf Species

One of the most critical decisions a turf manager can make is choosing the best grass for the customer. As with most decisions, research and background information are important in the selection process. If the grass species chosen turns out to be inappropriate, changing to another can be costly, labor intensive and possibly damaging to your professional reputation. Thus, it pays to consider the choice carefully.

First, interview the client. Ask questions such as "How much traffic do you expect on the turf?" "Is dark green color important, or will light green be acceptable?" and " How much budget is available for watering, fertilizing, mowing and pest control?"

In the interview, provide a long-term perspective for the client. The cost of seed and the time for establishment are small compared to the inputs required for maintenance over the coming years.

Steer the client away from the notion that the cost of installation and establishment time is the major reason for choosing a grass. You may wish to invest in a photo library consisting of color pictures of the various species adapted to your local area to show clients.

Successful grass selection begins with good landscape design, and selecting the right species for the right site is crucial. So, after the interview, perform a landscape inventory and analysis.

To inventory, walk through the landscape, gathering information. Identify opportunities and constraints of the area. Note wind patterns, existing trees and shrubs, existing turf, the condition of the turf, slope of the land, and shade/sun exposure.

Take a soil probe to the site and extract a few soil cores. Squeeze the soil to get a feel for clay, silt and sand content. Confirm your initial observations with a soil test. Virtually half of the turf plant grows underground, so it is critical to determine if the soil is suitable to encourage root growth. In general, most grasses prefer a slightly acidic to neutral pH, an organic matter content of 3 percent to 5 percent and enough pore space to permit drainage and air exchange.

The site inventory should be thorough, noting and photographing the features that make the site unique. Analysis can then be done to evaluate the importance of the condition. For example, an inventory might contain a note that the turf is diseased with powdery mildew, and that there are several large shade trees overhead.

The analysis would consider whether the trees should be removed or pruned, or if enough sun is received to allow any grass species to thrive.

In all cases, strive to put the right plant in the right place. This is especially important when considering traffic patterns. Wear tolerance varies among species, so take special notice of existing wear patterns or traffic flow markings in the existing landscape.

MAINTENANCE NEEDS. Combine the information gathered in the client interview and the notes/observations obtained in the site inventory/analysis to establish a target level of maintenance. In general, it will fall into one of several categories:

Very Low Maintenance: These are turf areas that receive no watering other than natural precipitation, no fertilization and are mowed at a fairly high height of cut. These turf areas are not much to look at, but serve their purpose. Rural cemeteries, airstrips, median strips and roadsides are typical uses for these low-maintenance turfs. Common bermudagrass, common bluegrass, buffalograss and forage-type tall fescues are good choices for very low-maintenance turfs.

Low Maintenance: Turfs in this level receive little to no watering, but enough to prevent drought stress. Irrigation frequency would be once every 21 to 28 days. Mowing height is fairly high, towards the high end in the desired range of each species. These turf areas typically are fertilized once a year. Industrial grounds, some home lawns, cemeteries, acreages, golf course roughs and picnic grounds are common sites for low-maintenance turfs. Common bermudagrass, zoysiagrass, common bluegrass, buffalograss, centipedegrass, bahiagrass, forage-type tall fescues, and fine fescues are good choices for low maintenance turfs.

Medium Maintenance: These turf areas receive a moderate level of inputs, including regular watering and frequent mowing, usually in the 2-inch to 3-inch range. These turfs are fertilized two to three times per year to encourage retention of green color and shoot, root and lateral growth. Golf course fairways, apartment buildings, office parks, athletic fields and most home lawns fall into this level of maintenance. Hybrid bermudagrass, improved zoysiagrass, premium bluegrass, bluegrass/perennial ryegrass mixtures, turf-type tall fescue, and St. Augustinegrass are good choices for medium maintenance lawns.

High Maintenance: These are turf areas that receive regular, high intensity inputs and require the greatest cost to maintain. They are frequently irrigated, and mowed at the lower end of the desired range in each species to produce a quality appearance. Fertilizer is applied frequently to these turfs, usually three to five times per year. In some situations, a "spoon feeding" regime is used, where fertilizer is applied every three weeks or so. Golf greens, estate grounds, upscale hotels, theme parks, some home lawns and certain office complexes are sites maintained at this level. Turf-type perennial ryegrass, premium bluegrass, hybrid bermudagrass and creeping bentgrass are good high maintenance turf choices.

KEY TRAITS. All of the factors in selection are interrelated to an extent. This is especially true if a turf species is maintained at a higher or lower level than is reasonable for the grass. For example, fertilization and irrigation affect mowing in that if you fertilize and irrigate a turf area heavily, the grass will require more frequent mowing. On the other hand, turf varieties that prefer moderate maintenance will generally become thin and open if fertilized and irrigated sparingly. In the latter scenario, drought stress and weed invasion due to an open stand will likely result.

Each species of grass has unique characteristics and attributes. More specifically, cultivars within a species express quite a range as well. The research group that is perhaps most interested in these differences is the National Turfgrass Evaluation Program. This program evaluates cultivars of turf in dozens of sites in each part of the nation to determine what grasses are best suited for each locale. (Information and summaries of research studies are available through NTEP, Beltsville Agricultural Research Center – West, Building 002, Room 013, Beltsville, MD 20705.)

The investigators at NTEP use the following factors and descriptions to guide their evaluation efforts:

Genetic Color – Shades of color range from light green to dark green. Americans generally prefer darker green grass, while Europeans prefer lighter green grass.

Leaf Texture – Describes the width of the leaves. Coarser-textured grasses, such as St. Augustinegrass, have a tougher "feel" and are not as thin or fine as perennial ryegrass or fine fescues, for example. Also, finer-textured grasses are often better for use in low-cut turf such as golf course fairways.

Density – This measures the amount of grass plants in an area. The larger number of plants per unit area, the greater the density. Grasses with high density ratings often give the lawn a more carpet-like look.

Growth Habit – This varies from upright to low growing along the soil surface. More upright growth requires more mowing. Some species, such as tall fescue, inherently have a more upright growth than low growers like Kentucky bluegrass. Plant breeders have changed this somewhat by developing "dwarf" or slower-growing tall fescues.

Uniformity – Having a lawn that is uniform in color, texture, density and growth habit is pleasing to the eye and desired by most people.

Disease/Insect Resistance – This relates to the turfgrass’ ability to resist disease and insect attacks. Some plants are more resistant to these pests because of their genetic makeup. Also, naturally occurring fungi, called endophytes, live within certain tall fescue, fineleaf fescue and perennial ryegrass varieties, helping these grasses repel insects.

Drought Resistance – This is the ability of a turfgrass to survive and/or thrive during drought conditions. The most desirable grass will maintain its green color and good quality during prolonged drought. However, for basic survival during drought, grasses often lose their green color and go dormant.

Water Use Efficiency – The amount of water needed by a turfgrass to maintain a certain level of quality or to provide acceptable performance. The water needs of turfgrass on an athletic field, for example, are often greater than the needs of a home lawn because of the "wear and tear" on the athletic turf. Also, turfgrasses vary widely in their water use efficiencies. Some grasses, like tall fescue, are large water users but have a deep root system to reach water that other grasses cannot reach.

Heat, Cold Tolerance – The turfgrass’ ability to survive extreme winter and summer temperatures.

Rate of Establishment – How quickly the turfgrass produces 100 percent ground cover. This is especially important in resisting weed invasion, controlling erosion and recovering from disease or insect damage.

Shade Tolerance – Trees are a major part of the landscape. Therefore, we need grasses that can survive and thrive in shaded areas.

Traffic/Wear Tolerance – This characteristic is important in parks, athletic fields, golf courses, playgrounds and home lawns.

Thatch Production – Some grass types produce thatch, or dead roots and stems, faster than soil microorganisms can decompose the thatch. Thatch is a place for diseases and insects to thrive, and it prevents water from reaching the turfgrass’ roots.

Nutrient Use Efficiency – Turfgrasses have varying nutrient use efficiencies, and the intensity of use and management will influence the turf’s nutrient needs.

Grasses are divided into warm- and cool-season species. Cool-season grasses are generally grown in areas where frosts and freezing temperatures are routine for a signifi

cant portion of the year, while warm-season grasses are grown in regions where mild to hot weather predominates. Buffalograss, zoysiagrass and creeping bentgrass are exceptions in that they are often grown successfully beyond traditional boundaries.

Cool-season grasses: The most widely grown cool-season grass is Kentucky bluegrass with its medium-textured, green to dark green turf of good density. The aggressive sod forming habit of bluegrass is attributable to its strong rhizome development, lateral spreading potential and excellent recuperative potential. It has fair high temperature tolerance and good to excellent cold temperature tolerance. Some cultivars are pest susceptible.

Tall fescue has the coarsest texture of any cool-season grass, as well as the lowest shoot density. The recuperative potential is quite low, as it is a bunch grass and does not spread laterally. Tall fescue has a very extensive root system that is used to draw on soil moisture reserves and resist insect feeding damage. Thus, it is considered pest resistant and drought tolerant. It has fair cold temperature tolerance and good to excellent heat tolerance. Tall fescue is used on home lawns, low budget athletic fields, acreages and highway turfs.

A group of grass species possessing needle-fine texture is the fineleaf fescues. The group is made up of hard fescue, sheep fescue, creeping red fescue and chewings fescue. Although there are minor differences, they are grouped together for practicality. Except for creeping red fescue, these are bunch grasses and do not spread significantly. They are medium to dark green and exhibit good to excellent shade tolerance, and are predominantly mixed with shade tolerant cultivars of bluegrass for use in turf areas that receive three to six hours of sun per day. Fine fescues are used on home lawns, cemeteries, golf course roughs and parks.

Perennial ryegrasses are also commonly mixed with Kentucky bluegrass with wear tolerance and quick establishment as the desired results. Ryegrasses are shiny, medium to dark green and fine to medium in texture. They germinate rapidly, making them useful in sports turfs. They have fair cold and warm temperature tolerance. Like the fescues, they are bunchgrasses and do not spread laterally. Perennial ryegrasses are used in home lawns, athletic fields, golf fairways and tees and on campus grounds.

Creeping bentgrass is a very low, very fine textured grass. It has good cold temperature tolerance and fair heat tolerance. It spreads readily through rhizomes. Bentgrasses are susceptible to a wide range of fungal diseases, and, along with a requirement for very frequent mowing, it is considered a high maintenance grass. It is used primarily on putting greens.

Warm-Season Grasses: Bermudagrass is one of the most widely used warm-season species, due to its many uses. Common bermu-dagrass is a bit coarse, having medium texture, while hybrid Bermudagrass is medium-fine.

Cold temperature tolerance is poor, while heat tolerance is good. All Bermudagrasses are aggressive spreaders, giving it excellent recuperative potential and rapid establishment. Because it tolerates close mowing and a wide range of soil types, it can be used on home lawns, athletic fields, golf courses, parks, cemeteries and industrial grounds.

Zoysiagrass is similar to Bermudagrass in that it has rhizomes and stolons, but differs with regards to cold tolerance, stiffness and growth rate. Some zoysia species have good cold temperature tolerance, and all have good to excellent heat tolerance. The growth rate is slow, and is quite stiff and tough compared to other grasses. The texture is medium, and the color is medium green color. Zoysiagrass has a deep root system, allowing it to avoid drought stress in many situations. Zoysiagrass is low growing and tolerates a low mowing height. It can be used on home lawns, school grounds, athletic fields, golf course fairways and tees and airfields.

A low maintenance, medium coarse grass, centipedegrass spreads by short, leafy stolons and forms a mat of low-growing stems and leaves. Centipedegrass is light to medium green in color. The cold temperature hardiness is quite poor, while heat tolerance is good. The shade tolerance is intermediate, better than bermudagrass. The recuperative potential is poor, due to its slow growth rate and spreading ability. Centipedegrass makes a good, tough turf where a low maintenance home lawn is desired. It can also be used in cemeteries and parks.

St. Augustinegrass forms an attractive blue-green, low growing turf of medium density and very coarse texture. The stems appear a bit compressed or squeezed together in the middle. This species spreads rapidly by stolons and has a medium to medium-deep root system. This allows for rapid establishment and good recuperative potential. Its poor low temperature tolerance limits usage where frosts commonly occur, yet is quite heat tolerant. It exhibits good shade tolerance, the best of the warm-season species. This feature allows for use on shady home lawns, cemeteries, parks and industrial grounds.

One of the few turfgrasses native to the United States, buffalograss is the quintessential low maintenance warm-season turf. Adapted to the central part of the U.S. from Texas to Minnesota, and Colorado to Illinois, it is grey-green in color and possesses a medium to fine texture. Improved cultivars provide a turf-type medium density. The cold and heat tolerance is good to excellent, while pest resistance is excellent. It requires no irrigation once established, and has a very low fertility requirement. It is slow growing and slow to establish, which limits its ability to recuperate from stress or injury. Therefore, buffalograss is limited to usage on low maintenance home lawns, golf course roughs, acreages, airfields, industrial sites and cemeteries.

An important point to remember in the selection of turfgrass is that a "magic grass" – one that uses little or no water, seldom needs mowing and withstands heavy use in a deeply shaded area – simply does not exist. The challenge for the turf manager is to use information to match the attributes and features of potential grass species with the needs and desires of the customer.