Selecting fairway grasses: Tried & true or something new?
What's the best turfgrass to use on fairways? Bentgrass? Bermudagrass? Ryegrass? Zoysiagrass? Many types are available, and recent cultivar improvements have multiplied the choices considerably. So how do you decide which turfgrass to use?
The short answer is: select the most-adapted species and cultivars for your area and intended use. Keep in mind that no perfect turfgrass exists. Each species and its cultivars have strengths and weaknesses. Rely on local research information to make informed decisions and talk to others using these turfgrasses under similar conditions in your area. However, don't just use one source of information. Base your selections on as much input as is reasonable and feasible. With that in mind, here is a description of the general characteristics of turfgrass species suitable for fairway use.
Bentgrasses Creeping and colonial bentgrasses fit in the "tried-and-true" category of fairway turfgrasses. They form excellent fairway turfs in their zonesof adaptation and vary in color from a dark blue-green to yellow-green. They produce dense, tight turfs that tolerate close mowing. Under close mowing, creeping bentgrass forms a dense, spreading turf, while colonial bents have a more upright habit.
Both species are well-adapted to cool-season regions, but creeping bentgrass is more widely adapted than the colonials, especially the recent cultivar developments. Many of the new creeping-bentgrass cultivars grow well in high temperatures. Thus, they offer greater potential for use in the transition zone and the warm humid and arid regions of the South. In addition, some of these new cultivars exhibit considerable improvement in turfgrass quality and disease resistance compared to older choices.
Fewer options are available with colonial bentgrass because turfgrass breeders historically have not emphasized cultivar development with this species. However, breeders and end users have a growing interest in this species and its potential for fairway use. This is likely to result in new cultivars for fairway use in the future.
Bentgrasses can develop thatch problems under fairway conditions. They are moderately tolerant of traffic stress and shade but are more prone to diseases than many other cool-season species. However, exceptions to these generalizations exist. Proper management and cultivar selection are key in dealing with these issues. Many university turfgrass-research programs have excellent data that can assist in the selection of cultivars and management practices for use on bentgrass fairways. Industry research data and nearby colleagues who are managing these grasses under similar conditions are good sources with which to supplement university information.
Blending creeping-bentgrass cultivars and mixing colonial bents with other species is a common practice for fairway turfs. Selecting the best cultivars, blends and mixes requires the use of common sense and sound selection criteria. Where feasible, on-site testing of potential options is useful. Compatible cultivars in a blend should have similar quality, color, texture and density ratings. Once you've narrowed your choices, use disease-resistance and stress-tolerance characteristics to select the blend components. The National Turfgrass Evaluation Program (NTEP) cultivar-evaluation trials conducted at universities across the United States and Canada are excellent sources of information for this type of decision-making.
Bermudagrass Bermudagrasses, common and hybrid, definitely fit in the "tried-and-true" category. They are widely adapted to warm-humid and warm-arid regions. The biggest limitation of bermudagrass is lack of cold hardiness. Common types are more winter hardy than the hybrids. It is not uncommon (for example, 1 out of 5 years) to lose fairways to winterkill injury in northern parts of the Transition Zone. Susceptibility to winter injury increases with reduced mowing heights, overseeding and increased traffic.
Both common and hybrid bermudagrasses form dense, low-growing turfs of moderate to excellent fairway playing quality. Common types tend to be more upright and open than the hybrid varieties. Both types have excellent wear and traffic tolerance when actively growing but perform poorly in the shade. Tifway (419) is the most widely used hybrid bermudagrass on fairways. Common types vary considerably. Thus, after planting, some strains become dominant due to their superior adaptation to the local environment.
Recent breeding efforts at universities and seed companies have emphasized the development of cultivars with improved cold tolerance. These improvements have enhanced bermudagrass adaptation for the northern portions of the Transition Zone. The improved cold performance is primarily in seeded, common bermudagrasses that provide moderate-quality playing conditions. Breeders are continuing to develop cultivars with improved quality, pest resistance and stress tolerance. It is likely that cultivars with even better performance in fairway conditions will be available in the future.
Bermudagrass goes into dormancy during the winter months in most areas where it is commonly grown. Therefore, overseeding is a common practice in these regions. Overseeding cool-season species such as perennial ryegrass, annual ryegrass, Poa trivialis or mixes of these species into bermudagrass fairways extends play and enhances aesthetic quality year round. Many Southern resorts and public courses rely on this technique to increase play and revenue during the winter.
Overseeding is not without its headaches. The transition from cool- to warm-season species in the spring and early summer often is difficult and stressful for the bermudagrass. Factors influencing this transition period and its subsequent stress on the bermudagrass include environment (temperature, humidity and light intensity), cultural practices (mowing height, nitrogen fertility and irrigation frequency) and the species and cultivars you used for overseeding. It is important to select grasses for overseeding that are weak performers under heat stress. This susceptibility to heat stress improves the transition to bermudagrass. Ironically, some of the best overall NTEP performers may not be the preferred overseeding choices because they thrive during the warm part of the year. Thus, they tend to persist as the bermudagrass breaks dormancy.
Perennial ryegrass The use of perennial ryegrasses in fairways has increased over the past 15 years, particularly in the cool-humid regions and northern parts of the Transition Zone. Breeders have considerably improved perennial-ryegrass varieties, so golf-course architects and superintendents have several excellent cultivars available to use in blends and mixes. Perennial ryegrasses establish rapidly, which makes them attractive for use on fairways that require frequent inter- or overseeding.
Perennial ryegrass forms a relatively dense, upright turf of medium to high quality for fairway playing conditions. It is extremely traffic tolerant, holding up well to wear injury and compaction stress. However, management of perennial-ryegrass fairways requires diligence, particularly in regions where disease pressure is high. Superintendents commonly treat ryegrass fairways with preventive fungicides for Pythium blight, brown patch and pink snow mold, to which this species is vulnerable. In areas where winter conditions are arid, perennial-ryegrass fairways require winter irrigation to prevent desiccation injury. Perennial-ryegrass turf is prone to direct low-temperature injury, especially in poorly drained areas where crown hydration occurs. Proper surface and internal drainage is key to reducing this type of injury. Earthworm castings also can be a problem on ryegrass fairways. Raising mowing heights and mixing with rhizomatous species, such as Kentucky bluegrass, are effective means to reduce this problem.
Despite these shortcomings, ryegrass provides good fairway playing conditions. Its rapid establishment makes it the species of choice when damaged turfs need repair. It also is a species that receives considerable interest from turfgrass breeders. Numerous cultivars are available and breeders continue to create many more as a result of strong demand for ryegrass for use in overseeding, fairway and sports-turf use.
Zoysiagrass Zoysiagrass fits both the "old" and "new" categories. It has been around for some time and finds limited use as a fairway turf in the Transition Zone. Zoysiagrass is slow to establish compared to other turfgrass species. Due to its slow establishment rate, you should sod zoysiagrass for best results. This species has excellent wear tolerance when it's actively growing but poor recuperative potential when damaged by traffic or stress. It is prone to direct low-temperature injury compared to cool-season turfgrasses and tends to weaken under shaded conditions. These characteristics limit its potential for use. Nevertheless, zoysiagrass forms dense, low-growing turf and provides excellent fairway playing quality with tight lies. Only limited new cultivar development has occurred in the past few years, but room definitely exists for cultivar improvement. More breeding efforts will be necessary for zoysiagrasses to become more widely used in fairways.
Bluegrass Kentucky bluegrass fits the "tried" category. Golf courses once used this species widely as fairway turf throughout the cool-humid and cool-arid regions. Kentucky-bluegrass cultivars typically form medium- to high-quality fairways, with the higher-quality playing conditions resulting from cultivars that tolerate mowing heights of 0.625 to 0.75 inch. Until recently, interest in Kentucky bluegrass as a fairway species had waned due to its relative inability to tolerate close mowing, compete with annual-bluegrass invasion and produce the tight lies desired by good golfers. Kentucky-bluegrass fairways are notorious for allowing the ball to settle into the turf, making it difficult to hit the golf ball with the desired backspin and control. Necrotic ring spot, summer patch and leaf-spot diseases reduce Kentucky bluegrass performance in many regions.
Recently, the industry has renewed its interest in using Kentucky bluegrass for fairway turf. Several new cultivars are performing well in reduced-mowing-height trials. NTEP trials initiated in the fall of 1995 include sites maintained under fairway conditions. These trials will continue through the 2000 growing season and will provide needed information on the use of these new cultivars in fairways.
Aggressive Kentucky-bluegrass cultivars are the best choices for fairway use. These types form excellent mixes with perennial ryegrass, recover rapidly from divot injury and tolerate reduced mowing heights. Turfgrass breeders in the private sector have introduced several new cultivars that tolerate closer mowing better than older types, and interest in the development of new cultivars with improved disease resistance and performance at reduced mowing heights continues.
Other bluegrasses Other bluegrass species offer potential for fairway use and may fit specific needs. Poa annua (annual bluegrass) and P. trivialis (rough-stalk bluegrass) fit this group. The mere mention of these grasses raises controversy. Are these weeds, turfgrasses or both?
Annual bluegrass makes an excellent fairway turf. In northern parts of the cool-humid and cool-arid regions, the "weed vs. turf" issue is a constant debate. A breeding program at the University of Minnesota has developed creeping-type cultivars, which they will refer to as "creeping bluegrass." The Pennsylvania State University also has started a Poa annua selection and breeding program. Between these two programs, you're likely to see improved cultivars for fairway use available in the near future. Some interest already exists in the potential use of annual bluegrass as a species for overseeding bermudagrasses during winter months. Annual bluegrass cultivars could provide excellent close-mowed fairways with rapid transition to bermudagrass as high temperatures return in the spring and early summer.
Rough-stalk bluegrass is adapted to the cool-humid region and grows well in poorly drained, shaded sites. It doesn't tolerate high-temperature stress, and it doesn't mix well with other species because it forms obvious patches that differ in color and texture from adjacent turf. In addition, under high-temperature stress, rough-stalk-bluegrass patches turn brown and fade out, leaving an undesirable appearance and poor playing quality. Therefore, this species' use is primarily limited to overseeding of bermudagrass for winter play. Poa trivialis sometimes occurs as a seed contaminant and can be a problem if you purchase inferior-quality seed.
Seashore paspalum Seashore paspalum fits the "something new" category. Native stands of seashore paspalum occur in warm coastal areas where salt water may limit the growth of other plants. These stands often experience drought stress, low nutrient availability and saline/sodic conditions. Seashore paspalum is a niche grass, but it has potential for seashore resorts and areas where nutrients are limiting and poor water quality exists.
Seashore paspalum produces low-growing, dense turfs that spread by rhizomes and stolons. Management is important in maintaining quality seashore-paspalum turfs. Overwatering and excessive nitrogen levels result in thatchy turf that is prone to scalping. At present, 'Adelaide' is the only commercially available cultivar. An extensive breeding and management program is underway at the University of Georgia, which promises to produce new cultivars with improved turfgrass quality.
Summing up So what's the best turfgrass to use on fairways? This is a question you can answer for yourself better than anyone else-it just requires a little research. Each species has strengths and weaknesses. Before selecting a particular species, gather information on its potential adaptation and performance under your conditions. Carefully examine information and trials to select the best cultivars for fairway use. Information is available from NTEP trials (visit the NTEP web site at http://www.ntep.org/ntep/), university and industry researchers, and extension educators. Use this information before making your selection.
Dr. Robert (Bob) C. Shearman is professor of horticulture at the University of Nebraska (Lincoln) and special projects coordinator for the National Turfgrass Evaluation Program (Beltsville, Md.).
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