Chapter 21 Selecting the proper grass.
Upon completion of this chapter, you should be able to
* list six factors used in the comparison of different turfgrasses
* list the information required by law on grass seed labels
* explain the differences between single-species plantings, single-species blends, and mixtures of species
Turfgrasses are among the oldest plants used for landscaping. They are the most common choice for surfacing the outdoor room. A neatly trimmed lawn of good quality is not only comfortable to walk on, but ideal for many athletic and recreational activities. Because the growing point of the turfgrass is at the crown of the plant, near the soil, it is protected. This permits turfgrasses to be mown and walked upon repeatedly.
Comparison of Turfgrasses
Most turfgrasses used in landscapes are perennial, surviving from one year to the next. Nearly all species reproduce from seed, although several can be reproduced vegetatively, without pollination and seed production. A typical grass plant produces new leaves throughout the growing season. During the growing season, the turfgrasses will increase beyond the number of seeds sown. One of the objectives of good lawn development is to encourage turf growth as quickly and as evenly aspossible.
* Grasses have differing growth habits, which result from the three different ways that new shoots are produced, Figure 21-1. Rhizome-producing (rhizomatous): A rhizome is a horizontal underground stem. New shoots are sent to the surface some distance out from the parent plant. Each new plant develops its own root system and is independent of the parent plant.
* Stolon-producing (stoloniferous): The shoots extending out from the parent plant are above ground. They are called stolons. New plants develop independently as described above. Some grasses are both rhizomatous and stoloniferous.
* Bunch-type: New shoots are produced from the sides of the plant, gradually increasing the plant's width.
[FIGURE 21-1 OMITTED]
Rhizome and stolon-producing grasses tend to reproduce more quickly and evenly than bunch-type grasses. Therefore, the bunch-type require more seed and closer spacing in order to cover an area quickly and without clumps.
Texture, Color, and Density
Grass texture is mostly a way of describing the width of the grass leaf (blade). The wider the blade is, the coarser will be the texture. Generally, fine-textured grasses are more attractive than coarse-textured grasses. They are also more expensive. The color of a grass and its density will also differ among species. Colors can vary from pastel greens to dark, bluish tones. Density refers to the number of leaf shoots that a single plant will produce. It can range from sparse to thick, depending upon the type of grass.
Size of Seed
The size of the seed is another reason for variation in the quality and quantity of grass seed mixes. Fine-textured grasses have very small seeds. Coarse-textured grass seeds usually are much larger. Thus, a pound of fine-textured grass seed contains considerably more seeds than a pound of coarse-textured grass seed.
Because of the greater number of seeds per pound, a pound of fine-textured grass seed plants a larger area of land. For example, a pound of fine-textured Kentucky bluegrass contains approximately 2,000,000 seeds. That number of seeds plants about 500 square feet of lawn. A pound of coarse-textured tall fescue contains 227,000 seeds; therefore, only 166 square feet can be planted with a pound of this particular seed.
Other comparisons can further point out the difference in seed sizes. For example, there are as many seeds in 1 pound of bluegrass as there are in 9 pounds of ryegrass; and as many seeds in a pound of bentgrass as there are in 30 pounds of ryegrass.
Soil and Climatic Tolerance
Most grasses, like almost all other plants, do best in good-quality, well-drained soil. However, every state contains landscape sites that fall short of the ideal conditions preferred for turfgrass success. Some grasses can adapt to a wide range of soil conditions, while others are very limited in their adaptability.
Similarly, some grasses tolerate high humidity and reduced sunlight; others do not. Some thrive in the subtropics and tropics; others are better-suited for temperate and subarctic regions.
Grasses are often grouped into two categories based upon the temperatures at which they grow best:
* Cool-season grasses are favored by daytime temperatures of 60 to 75 degrees F.
* Warm-season grasses are favored by daytime temperatures of 80 to 95 degrees F.
Figure 21-2 shows the peak growth rates of the two types of grasses. Knowledge of the optimum growing temperatures of grasses explains why northern lawns are often brown and dormant in midsummer when the days are very warm. Likewise, warm-season grasses do not really flourish in early spring and late fall when temperatures fall below the optimum temperature.
Common Warm-Season Common Cool-Season Grasses Grasses Bermuda grass Kentucky bluegrass zoysia grass red fescue centipede grass colonial bentgrass carpet grass ryegrass St. Augustine grass Bahia grass buffalo grass
[FIGURE 21-2 OMITTED]
Figure 21-3 illustrates the climatic regions of the continental United States that are favorable for the growth of the grasses listed and others. Any seed purchased for planting in a certain climatic region should be composed of the appropriate grasses.
Under the same conditions of use, some grasses will survive and others will quickly wear away. Some will accept heavy use and recover quickly, while others will recover much more slowly. Some can accept the compaction of heavy foot traffic and still look good; yet others may discolor and slow their rates of growth.
Disease and Insect Resistance
Certain grasses possess greater resistance than others to insect and disease pests. The resistance may be natural or may have developed through the efforts of plant breeders. Many grasses are continually being improved by horticultural scientists searching for features such as better color, resistance to drought, shade tolerance, and pest resistance.
[FIGURE 21-3 OMITTED]
In "A Comparison Chart for Turfgrasses" in this chapter, many of the most commonly used turfgrasses are compared.
Purchasing Grass Seed
Grass seed is sold in small quantities through retail outlets such as garden centers, supermarkets, hardware stores, and department stores. It is also sold in bulk amounts through wholesale suppliers. Professional landscapers usually purchase seed wholesale. However, most clients have purchased packaged seed from retailers in the past. They may not understand why the seed selected by the landscaper is priced higher than expected. Landscapers must be prepared to explain why all grass seeds are not alike and how the quality of seed is measured.
The key to determining the quality of grass seed is the seed analysis label. The seed analysis label, which by law must appear on every package of seeds to be sold, gives a breakdown of the contents of the seed package on which it appears. The analysis label may be on the package itself, or, if the seed is being sold in large quantities, on a label tied to the handle of the storage container.
While legal definitions vary somewhat from state to state, most analysis labels contain the following information:
Purity. The percentage, by weight, of pure grass seed. The label must show the percentage by weight of each seed type in the mixture.
Percent Germination. The percentage of the pure seed that was capable of germination (sprouting) on the date tested. The date of testing is very important and must be shown. If much time has passed since the germination test, the seed is older and less likely to germinate satisfactorily.
Crop Seed. The percentage, by weight, of cash crop seeds in the mixture. These are undesirable species for lawns.
Weeds. The percentage, by weight, of weed seeds in the mixture. A seed qualifies as a weed seed if it has not been counted as a pure seed or a crop seed.
Noxious Weeds. Weeds that are extremely undesirable and difficult to eradicate. The number given is usually the number of seeds per pound or per ounce of weed seeds.
Inert Material. The percentage, by weight, of material in the package that will not grow. In low-priced seed mixes, it includes materials such as sand, chaff, or ground corncobs. Inert material is sometimes added to make the seed package look bigger. At other times, the inert material is already present in the seed and is not removed because the cost involved would raise the price of the seed.
Three sample analyses follow. Study the contents of each mixture and determine which would probably cost the most and which the least.
It is likely that Mixture C would be the most expensive. It contains the highest percentage of fine-textured grasses, no coarse grasses, and the lowest percentage of weeds. Mixture A would probably cost the least, since it contains a high percentage of coarse-textured grasses, the lowest percentage of fine grasses, and the greatest percentage of weeds. None of the mixtures is very poor in quality, since there are no crop or noxious weed seeds claimed by any.
Mixture A Fine-Textured Grasses 12.76 percent red fescue 85 percent germ. 6.00 percent Kentucky bluegrass 80 percent germ. Coarse Grasses 53.17 percent annual ryegrass 95 percent germ. 25.62 percent perennial ryegrass 90 percent germ. Other Ingredients 2.06 percent inert matter 0.39 percent weeds--no noxious weeds Mixture B Fine-Textured Grasses 38.03 percent red fescue 80 percent germ. 34.82 percent Kentucky bluegrass 80 percent germ. Coarse Grasses 19.09 percent annual ryegrass 85 percent germ. Other Ingredients 7.72 percent inert matter 0.34 percent weeds--no noxious weeds Mixture C Fine-Textured Grasses 44.30 percent creeping red fescue 85 percent germ. 36.00 percent Merion bluegrass 80 percent germ. 13.54 percent Kentucky bluegrass 85 percent germ. Coarse Grasses None claimed Other Ingredients 5.87 percent inert matter 0.29 percent weeds--no noxious weeds
Mixtures, Blends, and Single-Species Lawns
Grass seed is commonly purchased either as a mixture or a blend. It is also available as a single species (such as all Kentucky bluegrass or all Chewings fescue). A mixture combines two or more different species of grass. A blend combines two or more cultivated varieties of a single species. Both mixtures and blends have their places depending upon the site and circumstances. Mixtures are most common in temperate zone landscapes; single-species plantings are more common in subtropical and tropical landscapes.
Mixtures sometimes have the disadvantage of variegated color and texture. This is a result of the different species they contain. They have the advantage of being able to tolerate mixed environmental conditions and can recover from insect and disease pests that would wipe out a single species.
Single-species turf plantings offer a more uniform appearance than mixtures. However, a single-species planting is often unable to adjust to severe changes in environmental conditions. It can also be completely destroyed by a single insect or disease invasion.
Blends attempt to retain the advantages of both mixtures and single-species plantings. If the cultivated varieties of the blend are carefully selected, a blend offers these advantages: uniform color and texture, resistance to damage from environmental changes, resistance to wear, resistance to pest injury, and the varieties in the blend will have similar maintenance needs.
A. Not all turfgrasses are alike. They can be compared using different factors. Insert the correct factor into each of the following sentences.
1. Adapting to differences in pH, aeration, fertility levels, humidity, light, and temperatures measures a turf's -- .
2. Rhizomatous, stoloniferous, and bunchtype are different -- of grasses.
3. Blade width, color variation, and the number of shoots per plant are measures of -- .
4. The ability of turf to withstand the compaction of foot traffic indicates its level of -- .
5. Certain grasses will suffer pest damage more than other grasses because of their -- .
6. One pound of fine-textured grass differs from a pound of coarse-textured grass in many ways. One way is in the number and -- of the seeds.
B. What could cause a very high-quality grass seed purchased in the south to be unsuitable for planting in the north?
C. Of the three seed mixtures A, B, and C shown in this chapter, which mixture is most likely to result in a sparse second-year lawn? Why?
D. Why is a grass seed mixture usually preferable to a pure, single-species seed?
E. List and define the important terms found on a grass seed analysis label.
1. Grow some grasses. Start flats or flowerpots of pure grass species in the classroom. Compare fine-leaf and broad-leaf types. If possible, also grow samples of warm-season and cool-season grasses for comparison.
2. Obtain several grass seed mixtures from various sources and in as many price ranges as possible. Rank the mixtures on the basis of package appearance, advertised claims, and brand names. Rank the mixtures again, using the seed analysis labels as the measure. How closely do the package claims match the actual facts about the mixture as shown on the labels? How closely does the price ranking follow the quality ranking?
3. Make a seed count. Weigh 1/4-ounce quantities of a fine-textured grass and a coarse-textured grass. Be as accurate as possible. Count the number of seeds in each measure. Do the fine-textured seeds outnumber the coarse-textured seeds?
NOTE: Do not use redtop for the coarse-textured grass in this exercise. Its seeds are atypically small for a coarse grass.
Jack E. Ingels
State University of New York
College of Agriculture and Technology
Cobleskill, New York
A Comparison Chart for Turfgrasses Cool Season Grass or Growth Leaf Species Warm Season Habit Texture Bahiagrass Warm Rhizomatous Coarse Bermudagrass Warm Stoloniferous Fine and rhizomatous Bentgrass, Cool Bunch-type (with Fine Colonial short stolons and rhizomes) Bentgrass, Cool Stoloniferous Fine Creeping Bentgrass, Redtop (see Redtop) Bentgrass, Cool Stoloniferous Fine Velvet Bluegrass, Cool Bunch-type or Fine Annual stoloniferous Bluegrass, Cool Rhizomatous Medium Canada Bluegrass, Cool Rhizomatous Fine Kentucky Bluegrass, Cool Stoloniferous Fine Rough Bromegrass, Cool Rhizomatous Coarse Smooth Buffalograss Warm Stoloniferous Fine Carpetgrass, Warm Stoloniferous Coarse Common Carpetgrass, Warm Stoloniferous Coarse Tropical Centipedegrass Warm Stoloniferous Medium Fescue, Cool Bunch-type Fine Chewings Fescue, Cool Rhizomatous Fine Creeping Red Fescue, Hard Cool Bunch-type Medium Fescue, Meadow Cool Bunch-type Coarse Fescue, Sheep Cool Bunch-type Fine Fescue, Tall Cool Bunch-type Medium to Coarse Gramagrass, Warm Rhizomatous Fine Blue Redtop (a Cool Rhizomatous Coarse bentgrass) Ryegrass, Cool Bunch-type Medium Annual Ryegrass, Cool Bunch-type Fine Perennial St. Augustinegrass Warm Stoloniferous Coarse Timothy, Cool Bunch-type Coarse Common Wheatgrass, Cool Bunch-type Coarse Crested Zoysiagrass Warm Stoloniferous Medium (Japanese and rhizomatous lawngrass) Zoysiagrass Warm Stoloniferous Fine (Manilagrass) and rhizomatous Zoysiagrass Warm Stoloniferous Fine (Mascarenegrass) and rhizomatous Mowing Fertilization. Pounds Grass Height/ of Nitrogen Per 1,000 Species Inches Square Feet Per Year Bahiagrass 1 1/2 to 2 1 to 4 Bermudagrass 1 to 2 4 to 9 Bentgrass, 1/2 to 1 2 to 4 Colonial Bentgrass, 1/2 or less 4 to 8 Creeping Bentgrass, Redtop (see Redtop) Bentgrass, 1/2 or less 2 to 4 Velvet Bluegrass, 1 2 to 6 Annual Bluegrass, Does not 1 or less Canada mow well Bluegrass, 1 to 2 1/2 2 to 6 Kentucky Bluegrass, 1 or less 2 to 4 Rough Bromegrass, Does not 1 or less Smooth mow well Buffalograss 1/2 to 1 1/2 1/2 to 2 Carpetgrass, 1 to 2 1 to 2 Common Carpetgrass, 1 to 2 1 to 2 Tropical Centipedegrass 1 to 2 1 to 2 Fescue, 1 1/2 to 2 2 Chewings Fescue, 1 1/2 to 2 2 Creeping Red Fescue, Hard Does not 1 or less mow well Fescue, Meadow 1 1/2 to 3 1 or less Fescue, Sheep Does not 1 or less mow well Fescue, Tall 1 1/2 to 3 1 to 3 Gramagrass, Does not 1 or less Blue mow well Redtop (a 1 1/2 to 3 1 to 2 bentgrass) Ryegrass, 1 1/2 to 2 2 to 4 Annual Ryegrass, 1 1/2 to 2 2 to 6 Perennial St. Augustinegrass 1 to 2 1/2 2 to 6 Timothy, 1 to 2 3 to 6 Common Wheatgrass, 1 1/2 to 3 1 to 3 Crested Zoysiagrass 1/2 to 1 2 to 3 (Japanese lawngrass) Zoysiagrass 1 2 to 3 (Manilagrass) Zoysiagrass Does not 2 to 3 (Mascarenegrass) mow well Grass Species Soil Tolerances Climate Tolerances Bahiagrass Infertile, acidic, Subtropical and and sandy tropical Bermudagrass Does well on a Warm temperate and wide range of soils subtropical Bentgrass, Moderately fertile, Temperate and Colonial acidic, and sandy seacoastal Bentgrass, Fertile, acidic, and Subarctic and Creeping moist temperate Bentgrass, Redtop (see Redtop) Bentgrass, Moderately fertile, Temperate and Velvet acidic, and sandy seacoastal Bluegrass, Fertile, neutral to Temperate and Annual slightly acidic cool subtropical Bluegrass, Infertile, acidic, and Subarctic and Canada droughty cool temperate Bluegrass, Fertile, neutral to Subarctic, temperate, Kentucky slightly acidic and cool subtropical Bluegrass, Fertile and moist Subarctic and cool, Rough shaded temperate Bromegrass, Infertile and droughty Dry and temperate Smooth Buffalograss Does well on a Dry temperate wide range of soils; and subtropical tolerant of alkaline soils Carpetgrass, Infertile, acidic, and Subtropical and Common moist tropical Carpetgrass, Infertile, acidic, and Humid subtropical Tropical moist and tropical Centipedegrass Infertile, acidic, and Subtropical and sandy tropical Fescue, Infertile, acidic, and Subarctic and Chewings droughty temperate Fescue, Infertile, acidic, and Subarctic and Creeping Red droughty temperate Fescue, Hard Fertile and moist; not Moist and temperate tolerant to droughty soil Fescue, Meadow Widely tolerant of all Moist and temperate but droughty soils Fescue, Sheep Infertile, acidic, well- Dry and temperate drained, and droughty Fescue, Tall Does well on a wide Warm temperate and range of soils subtropical Gramagrass, Does well on a wide Dry and subtropical Blue range of soils Redtop (a Does well on a wide Subarctic, temperate, bentgrass) range of soils and cool subtropical Ryegrass, Fertile, neutral to Temperate and Annual slightly acidic and subtropical moist Ryegrass, Fertile, neutral to Mild and temperate Perennial slightly acidic and moist St. Augustinegrass Does well on a wide Subtropical and range of soils tropical seacoastal Timothy, Fertile, slightly Subarctic and cool Common acidic, and moist temperate Wheatgrass, Does well on a wide Subarctic and cool Crested range of soils temperate Zoysiagrass Does well on a wide Temperate, subtropical, (Japanese range of soils and tropical lawngrass) Zoysiagrass Does well on a wide Subtropical and (Manilagrass) range of soils tropical Zoysiagrass Does well on a wide Warm subtropical and (Mascarenegrass) range of soils tropical How Established. If Grass Seeded, Pounds Per Species Uses 1,000 Square Feet Bahiagrass Utility turf; good for Seeded at 6 to 8 use along roadways Bermudagrass Sunny lawn areas; good Plugging or seeded at general purpose turf 1 to 1 1/2 for athletic fields, parks, home lawns Bentgrass, Areas where intensive Seeded at 1/2 to 2 Colonial cultivation is practical Bentgrass, Golf greens and other Sprigging or seeded at Creeping uses where intensive 1/2 to 1 1/2 cultivation is Bentgrass, Redtop practical (see Redtop) Bentgrass, Shaded, intensively Seeded at 1/2 to 1 1/2 Velvet cultivated areas Bluegrass, Not planted Does not apply Annual intentionally; but common in intensively cultivated turfs during spring and fall Bluegrass, A soil stabilizer Seeded at 1 to 2 Canada Bluegrass, Sunny lawn areas; good Seeded at 1 to 2 Kentucky general purpose turf for athletic fields, parks, and home lawns Bluegrass, Some use on shaded, Seeded at 1 to 2 Rough poorly drained sites Bromegrass, A soil stabilizer Seeded at 1 to 2 Smooth Buffalograss Useful in semiarid Seeded at 3 to 6 sites as a general purpose lawn grass Carpetgrass, Utility turf; good for Seeded at 1 1/2 to Common use along roadways and 2 1/2 as a soil stabilizer Carpetgrass, Utility turf; good for Seeded at 1 1/2 to Tropical use along roadways and 2 1/2 as a soil stabilizer; can be used as a lawn grass in tropics Centipedegrass Utility turf; also Seeded at 1/4 to 1/2 usable as a low-use lawn grass Fescue, Shaded sites with poor Seeded at 4 to 8 Chewings soil Fescue, Shaded sites Seeded at 3 to 5 Creeping Red Fescue, Hard A soil stabilizer Seeded at 4 to 8 Fescue, Meadow Utility turf; good for Seeded at 4 to 8 use along roadways Fescue, Sheep A soil stabilizer Seeded at 3 to 5 Fescue, Tall Utility turf; good for Seeded at 4 to 8 use along road-ways; new cultivars (Brookston, Olympic, and Rebel) good for lawns Gramagrass, Utility turf; good for Seeded at 1 to 2 Blue use along road-ways and in arid sites Redtop (a Utility turf; good for Seeded at 1/2 to 2 bentgrass) use along road-ways and in poorly drained areas Ryegrass, Useful for quick and Seeded at 4 to 6 Annual temporary lawns in the temperate zone and for winter color in the subtropic zones Ryegrass, Used in mixed species Seeded at 4 to 8 Perennial lawns and as an athletic turf St. Augustinegrass A good lawn grass with Sprigging excellent shade tolerance Timothy, Utility turf; good for Seeded at 1 to 2 Common athletic fields in cold regions where preferable species won't survive Wheatgrass, Useful as a general Seeded at 3 to 5 Crested purpose turf on droughty sites Zoysiagrass Useful as a general Plugging (Japanese purpose turf for home lawngrass) lawns, parks, and golf courses, especially in warmer regions Zoysiagrass A good lawn grass Plugging (Manilagrass) Zoysiagrass A soil stabilizer and Plugging (Mascarenegrass) groundcover
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|Title Annotation:||SECTION 2 Landscape Contracting|
|Author:||Ingels, Jack E.|
|Publication:||Landscaping Principles and Practices, 6th ed.|
|Date:||Jan 1, 2004|
|Previous Article:||Chapter 20 Installing landscape plants.|
|Next Article:||Chapter 22 Lawn construction.|