Perennial Ryegrass - Turf Grass

Perennial Ryegrass (Lolium Perenne L.)

Origin: Perennial Ryegrass (Lolium Perenne L.; also called English Ryegrass) is a temperate (cool-season) perennial grass that is native to Europe, temperate Asia, and North Africa. It has been widely distributed to other parts of the world, including North and South America, Europe, New Zealand, and Australia.

General Information: Perennial Ryegrass is valued for high yield potential, fast establishment, reduced tillage renovation applications, and use on heavy and waterlogged soils. Perennial Ryegrass is the fastest establishing species of all the turf grasses. It prefers milder climates, but tolerates temperatures down to minus 16-18°C without snow cover. With a snow cover, Ryegrass tolerates even lower temperatures. In temperate regions, Perennial Ryegrass is a true perennial with high persistence. It can be used on most soil types with the exception of very wet land. Perennial Ryegrass exists in early, intermediate and late types in respect to heading and spring growth. Perennial Ryegrass has very high wear tolerance due to fast regrowth of tillers and leaves. This makes the species an essential ingredient in mixtures for sports. It demands regular fertilisation and cutting.

Description/Taxonomy: Perennial Ryegrass is a temperate (cool-season) bunchgrass that can behave as an annual, short-lived perennial, or perennial depending on environmental conditions. It resembles Annual Ryegrass (Lolium multiflorum Lam.), though the collar and blade of Perennial Ryegrass are more narrow and seeds are awnless.

Vegetative Characteristics: Leaves of Perennial Rryegrass are folded in the bud (in contrast to Annual Ryegrass (Lolium multiflorum L.) in which the leaves are rolled). Leaf blades are 2 to 6 mm (.08-.24 inches) wide, 5 to 15 cm (2-15inches) long, sharply taper-pointed, and keeled. Blades are bright green, prominently ridged on the adaxial (upper) surface, and smooth, glossy, and glabrous (hairless) on the abaxial (lower) surface. Leaf margins are slightly scabrous (rough to the touch, covered with minute serrations). Blades increase in size from the first to the seventh leaf on a tiller, although tillers rarely have more than three live leaves at one time. Leaf sheaths usually are not keeled, compressed but sometimes almost cylindrical, glabrous, pale green, and reddish at the base. Sheaths may be closed or split. The collar is narrow, distinct, glabrous, and yellowish to whitish-green. Auricles are small, soft, and claw-like. The ligule is thin-membranous, from 0.5 to 2.5 mm (.02-.1 inches), obtuse (rounded at the apex), and may be toothed near the apex.

Root System: The shallow root system is highly branched and produces adventitious roots from the basal nodes of tillers. Perennial Ryegrass has no rhizomes or stolons. It will, however, produce a dense and closely knit sward or turf with high plant densities and proper management.

Cultivar Groups: Perennial Ryegrass cultivars are grouped into three maturity categories; early, intermediate, and late. This is helpful, but groupings are somewhat arbitrary, since phenological development is a continuum and is affected by temperature and photoperiod. Thus, without common criteria and standardised reporting procedures for maturity categories, there is substantial overlap.

Cultivars: Including both forage and turf types, there are more than 100 Perennial Ryegrass cultivars listed in the “Grass Varieties of the US” document (1995). There are more than 500 named cultivars are in the 1996 OECD list of cultivars (OECD, 1996). Information on cultivars also is available from the Oregon Ryegrass Growers Seed Commission and through the Germplasm Resources Information Network.

Cultivars from DLF Triforium include: Aiken, Allstarter, Bellini 1, Berlioz 1, Bizet 1, Capri, Cassiopeia, Chardin, Clementine, Cleopatra, Columbine, Conrad 1, Cyrena, Dickens 1, Disco, Doremi, Double 4n, Duparc, Dylan, Enesco, Esquire, Essence, Forever, Greenblush, Greenfair, Greengilde, Greensky, Greenway, Himalaya, Hugo 1, Keystone, Kokomo, LeClair, Madrid, Malibu, Margarita, Melbourne, Mercitwo, Montreux, Natasha, Neruda 1, Passion, Platinum, Ponderosa, Pontiac, Poseidon, Regal 5, Rokade, Rosemary, Stolawn, Stravinsky, Taya, Tetragreen 4n, Tophat 2, Troya, Venice.

Some Australian Cultivars include:

• Very early maturing diploids: Boomer, Fitzroy, Kangaroo Valley, Matilda, Meridian Plus AR1, Skippy, Drylander, and Everlast;
• Early maturing diploids: Ausvic, Camel, Kingston, Roper, Victorian, and Tomson;
• Mid season diploids: Avalon, Bolton, Grasslands Commando; Bronsyn Plus AR1, Cannon, Cannon AR1, Cowmax, CM105HP, Extreme, Grasslands Nui, Lincoln, Prolong, Samson, Samson AR1; and
• Late season tetraploids: Bealey, Canasta, Grasslands, Optima, and Quarte.

Turf Use: Use of perennial ryegrass for turf has increased in recent years with selection of more dense and persistent turf types. It is one of the most versatile of all turf grass species. For turf, Perennial Ryegrass is used alone or in combination with other grasses. Significant disease problems and limited cold and heat tolerance, however, limit its persistence and zone of adaptation. For the southern region of the U.S., Perennial Ryegrass’s intolerance to high temperature has become an advantage; it is used to overseed dormant bermudagrass (Cynodon dactylon L.) on Southern lawns and sports fields during the winter months. The Perennial Ryegrass thins and often dies during hot spring and summer weather, allowing the transition to Bermudagrass turf thus maintaining an active surface suitable for golf and other sports. Recent improvements in turf cultivars include improved disease resistance, high temperature tolerance, and darker green color. European evaluation trials include tolerance to close mowing and traffic. One caution here for forage use, however, is that “turf-type” cultivars of Perennial Ryegrass often have a fungal endophyte added for increased pest resistance and persistence. These endophyte-infected cultivars should be used with caution, if at all, for livestock feed due to the presence of toxins (primarily lolitrim b and ergovaline).

Optimum Growth Conditions: Perennial Ryegrass is best adapted to cool, moist climates. Optimum growth occurs between 20 and 25° C (68-77° F). Perennial Ryegrass grows best on fertile, well-drained soils but has a wide range of soil adaptability. It is tolerant of poorly-drained soils and frequently is used in these environments. It grows well in early spring and fall, but during the hot summer months it becomes dormant. Even with irrigation or abundant summer rainfall, Perennial Ryegrass production suffers due to high temperature stress when day temperatures exceed 30° C (86° F) and night temperatures exceed 25° C (77° F). It is more sensitive to temperature extremes and drought than Annual Ryegrass.

Soils: It tolerates both acid and alkaline soils, with a pH range of approximately 5.0 to 8.3. Similar to Tall Fescue, Perennial Ryegrass is adapted to shade in the warmer portions of a cool, humid climate where winter kill is not a problem.

Diseases: In humid climates, perennial ryegrass is susceptible to ergot (Claviceps purpurea Tul.) which is toxic to livestock and to stripe smut (Ustilago striiformis (West.) Niessl.) which can cause grass to be unpalatable. Many cultivars are susceptible to leaf spots (Drechslera spp.), fusarium (Fusarium spp.), brown blight (Drechslera siccans), and other fungus diseases in hot, humid climates. Most varieties also are susceptible to snow molds (or moulds) (Typhus spp., Fusarium spp., and Sclerotinia spp.) and many are susceptible to mildews of various sorts including powdery mildew (Erysiphe graminis DC. Ex Merat.). In the northeastern and northwestern sections of the U.S., crown rust caused by Puccinia coronata Corda, Stem rust caused by P. graminis subsp. graminicola Z. Urban, bacterial wilt caused by Xanthomonas campestris pv. Graminis, and Drechslera (Helminthosporium) spp. can be problems with Perennial Ryegrass depending on weather conditions and cultivar susceptibility. Stem rust often is a problem in late spring and early summer, especially if forage is allowed to accumulate. Stem and crown rust occur in late summer and early fall. Although rust is not toxic to livestock, it can affect palatability. For horses especially, the spores from rusts and smuts can be a significant respiratory problem. High fertility and harvesting the accumulated forage reduce rust problems. For turf and grass seed production, chemical control measures are available. Most, however, are not registered for forage use.

Insects: Grass grub (Costyletra spp.) is an important pest of Ryegrass. Grub larvae eat Ryegrass roots, rendering the plant more susceptible to drought. In New Zealand, the Argentine stem weevil is a major Perennial Ryegrass problem. Perennial Ryegrass is resistant to this weevil (and other pests) if the grass is infected by the fungal endophyte. Presence of the endophyte, however, is linked to the occurrence of a neurological disorder in livestock known as Ryegrass Staggers. For turf applications, the chinchbug and sod webworm are additional pest problems. The European cranefly (Tipula paludosa) is of local importance in the Pacific Northwest. Chemical control measures are available, but seldom economical. Typically, pastures are reseeded with renovation techniques when stands are lost to the European cranefly.