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Ch. 12, pp. 8 - 11

[Growth Characteristic: warm season | cood season ]

Perennial Ryegrass
Perennial Ryegrass

These grasses grow best during the spring and fall seasons when it is cool. Cool season grasses struggle during the summer. They may or may not go dormant during the winter cold. These are mostly bunch grasses, meaning they grow in bunches and do not have stolons or rhizomes. The exception is Kentucky bluegrass which produces rhizomes. Three cool season grasses (perennial ryegrass, annual ryegrass, and tall fescue) grow by producing shoots in bunches (tillers) from the base of each plant. Therefore, it is important to have uniform seed distribution when seeding cool season grasses to avoid bunchy turf.
Ryegrass, (Lolium species) are one of three types: perennial ryegrass (L. perenne), annual ryegrass (L. multiflorum), and hybrid crosses between the two (L. hybridum). Ryegrasses normally do not grow year after year in the southwest in the low desert. Therefore perennial ryegrass is not truly perennial in the low elevation deserts of the southwest. However, the higher the elevation and the cooler the temperatures, ryegrass can grow year after year. Perennial ryegrasses are better adapted to closer mowing conditions than annual ryegrass, since they have many narrow leaves on each individual shoot. They also have more shoots per square inch of turf than annual ryegrass.
Perennial ryegrass can be identified by recognizing some prominent features. The underside of the leaves are very shiny and smooth. The leaves have a series of ribs on the surface which cover the entire leaf surface. In the middle of the leaf there is a visual depression which forms the midrib.
Perennial ryegrass can be mowed as low as 1/4" with special management. Moreover, it is adapted to mowing heights of 3/4" to 1 1/2" with a reel mower. It also is suitable for mowing heights of 1 1/2" - 2 1/2" using a rotary mower, which is more common in the landscape industry, and for home lawns.
Perennial ryegrass is often sold as a blend. A blend is two or more varieties of the same species of grass. An example of a perennial ryegrass blend would be 50% Palmer and 50% Prelude. Each of these are perennial ryegrasses. A mixture is two or more different species of grass mixed together. A mixture of Kentucky bluegrass and perennial ryegrass may be available at high elevation nurseries and garden centers. This is a mixture because it contains two different species (Kentucky bluegrass and perennial ryegrass) or more.
Annual ryegrass is lighter in color then perennial ryegrass. It also has a wider leaf blade, and the mid vein is not as distinct as that of perennial ryegrass. An enlarged appendage can be found on annual ryegrass where the leaf attaches to the grass shoot. It resembles large collars on a dress shirt and is called an auricle. These auricles wrap around the shoot and are termed "clasping auricles." These are easily noticed on annual ryegrass but much less so on perennial ryegrass.
Annual ryegrass does not tolerate frequent close mowing. It is best adapted to mowing heights of 2 to 3 inches using a rotary type mower.
Annual ryegrass
Annual Ryegrass
A cross between annual ryegrass and perennial ryegrass has produced a new species of grass called Lolium hybridum. The intention is to have a grass with better qualities than annual ryegrass, along with the ease of spring transition of the annual ryegrass, as well. Most varieties are more upright than the perennial ryegrasses and are lighter in color. The varieties "Transtar" and "Froghair" have been sold in Arizona, mostly to golf courses and landscapers who need to be assured of an easy transition back to bermudagrass in the early summer.
Annual and perennial ryegrass varieties should never be mixed together in a seed mixture. The resulting lawn will look very weedy and have differences in color, texture, and result in poor uniformity.
Note that hybrid ryegrass is not a mixture of annual and perennial ryegrass, but is a separate grass species by itself.
During the fall, bermuda grasses can be over seeded with ryegrass. Both annual, perennial ryegrasses or the hybrid can be used. These grasses germinate quickly and have excellent seedling vigor, thus establishing turfs easily. (For more information concerning ryegrasses, see Extension Bulletin No. 8652, Over seeding bermuda grasses.)
Tall Fescue, (Festuca arundinaceae) is a cool season grass which has improved turfgrass qualities. It is more heat tolerant than the ryegrasses. Other fescue species are sometimes planted in higher elevation locations. These include: Sheep fescue, (F. ovata), California fescue, (F. californica), Red fescue, (F. rubra), and others.
Tall fescue has a deep root system that allows better survival during drought periods if soil moisture is available. It's normal range of adaptation does not include the low desert areas of the southwest. It does have fair shade tolerance, and has been used to some success in heavily shaded areas, replacing St. Augustine grass, because of its ease of maintenance, year round color, and shade tolerance.
Tall Fescue
Tall Fescue
Tall fescue has leaves which are about as wide as annual ryegrass, both of which are wider than those of perennial ryegrass. The vein pattern is different from the ryegrass as well. Tall fescue has a flat leaf with many large veins clearly visible on the leaf surface. It does not have midrib like perennial ryegrass. Also, hook-like hairs are found on the leaf margins, pointing toward the leaf tip. These hairs can be felt by running your thumb and finger along the leaf margin starting from the leaf tip towards the base. Tall fescue is easily established from seed in the middle of September in Tucson, and by the first week of October in Phoenix. In high desert areas planting is best done in September; the second choice is spring. Fall planting allows better root development so that the root system is developed before the hot summer weather. The underlying bermuda or St. Augustine must be eliminated first, by spraying the actively growing warm season grass with Round-Up herbicide in the summer.
Tall fescue is not to be used as an overseed on top of bermudagrass. The result will be a clumpy and irregular lawn.
On prepared ground, tall fescue should be planted at the seed rate of 8-10 lbs. of seed per 1000 square feet. Increased seeding rates will result in a weakened lawn condition over time. Tall fescue is best mowed with a rotary mower at 2.0 or 2.5 inches as the base height. For shady areas and during the summer months in the low desert, raise the mowing height to 3.0 inches. Return to lower mowing height during the following November.
Kentucky bluegrass (KBG), (Poa pratensis) can be established from either seed or sod. Sometimes Rough-stalked bluegrass, (Poa trivialis) a finely textured, bright green perennial grass is mixed in shady lawn mixtures for its tolerance of shade, and damp soils, along with creeping red fescue (Festuca rubra). KBG produces rhizomes but no stolons. These rhizomes help produces a thick dense turf. Leaf blades have a tip that is shaped like the front of a canoe. Leaves have a prominent midrib and fine obscure veins. Because KBG produces only rhizomes and no stolons less thatch is produced than bermuda grass. Certain varieties of KBG are fairly shade tolerant, such as `Glade' and `Nugget'. KBG is sometimes sold as seed with other grasses. These may include fine fescue (for shade tolerance) and perennial ryegrass (used as a nurse or companion grass). Do not purchase seed of a KBG mixture which has 10% or more ryegrass seed in the mixture. KBG are best planted in the fall in high desert locations or spring in mountain areas like Flagstaff. KBG will not perform well in low desert areas, and should not be used in fall overseeding of bermudagrass lawns.

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