Index of Species Information

SPECIES:  Lolium perenne


SPECIES: Lolium perenne
AUTHORSHIP AND CITATION : Sullivan, Janet. 1992. Lolium perenne. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: [].
ABBREVIATION : LOLPER SYNONYMS : NO-ENTRY SCS PLANT CODE : LOPE COMMON NAMES : perennial ryegrass English ryegrass crested ryegrass TAXONOMY : The scientific name for perennial ryegrass is Lolium perenne L. Perennial ryegrass belongs to the family Poaceae, tribe Triticeae (Hordeae) [16]. It is closely related to the genus Festuca; numerous natural hybrids between ryegrasses and European species of Festuca have been reported [16]. Natural hybrids have resulted in great variation in the characteristics of ryegrass species. Some authors recognize the following varieties or subspecies [13,23,24]: Lolium perenne subsp. perenne Lolium perenne var. cristatum Pers. Some authors distinguish annual ryegrass (L. p. ssp. multiflorum (Lam.) Husnot.) and perennial ryegrass (L. p. ssp. perenne) as separate species due to distinct structural characteristics, even though annual ryegrass was derived artificially from perennial ryegrass and they readily hybridize [14,16]. Common ryegrass (Lolium spp.) is a commercial mixture of ryegrass species which is mostly annual ryegrass but usually contains a substantial percentage of perennial ryegrass and annual-perennial hybrids [49,57]. LIFE FORM : Graminoid FEDERAL LEGAL STATUS : No special status OTHER STATUS : NO-ENTRY


SPECIES: Lolium perenne
GENERAL DISTRIBUTION : Native to Eurasia, perennial ryegrass is widely planted in North America for lawns and has many agricultural uses. It occasionally escapes and becomes naturalized, mostly in waste places and roadsides [13,39,40,46,57]. It is found from Newfoundland to Alaska, south to Virginia and California, occasionally farther south [23]. The most concentrated agricultural use of perennial ryegrass are in the humid southeastern United States and the mediterranean and temperate climates of the Pacific Northwest and California, west of the Cascade Range and the Sierra Nevada [39,40]. ECOSYSTEMS : FRES10 White - red - jack pine FRES11 Spruce - fir FRES12 Longleaf - slash pine FRES13 Loblolly - shortleaf pine FRES14 Oak - pine FRES15 Oak - hickory FRES16 Oak - gum - cypress FRES17 Elm - ash - cottonwood FRES18 Maple - beech - birch FRES19 Aspen - birch FRES20 Douglas-fir FRES21 Ponderosa pine FRES22 Western white pine FRES23 Fir - spruce FRES24 Hemlock - Sitka spruce FRES25 Larch FRES26 Lodgepole pine FRES27 Redwood FRES28 Western hardwoods FRES34 Chaparral - mountain shrub FRES36 Mountain grasslands FRES37 Mountain meadows FRES38 Plains grasslands FRES39 Prairie FRES41 Wet grasslands STATES : AL AK AZ AR CA CO CT DE GA HI ID IL IN IA KS KY LA ME MD MA MI MN MS MO MT NE NV NH NJ NM NY NC ND OH OK OR PA RI SC SD TN TX UT VT VA WA WV WI WY AB BC MB NB NF NS ON PE PQ SK BLM PHYSIOGRAPHIC REGIONS : 1 Northern Pacific Border 2 Cascade Mountains 3 Southern Pacific Border 4 Sierra Mountains 5 Columbia Plateau 6 Upper Basin and Range 7 Lower Basin and Range 8 Northern Rocky Mountains 9 Middle Rocky Mountains 10 Wyoming Basin 11 Southern Rocky Mountains 12 Colorado Plateau 13 Rocky Mountain Piedmont 14 Great Plains 15 Black Hills Uplift 16 Upper Missouri Basin and Broken Lands KUCHLER PLANT ASSOCIATIONS : NO-ENTRY SAF COVER TYPES : Perennial ryegrass probably occurs in most SAF Cover Types. SRM (RANGELAND) COVER TYPES : Perennial ryegrass probably occurs in most SRM Cover Types. HABITAT TYPES AND PLANT COMMUNITIES : NO-ENTRY


SPECIES: Lolium perenne
IMPORTANCE TO LIVESTOCK AND WILDLIFE : Perennial ryegrass is a palatable and nutritious forage for all classes of livestock and most wild ruminants [14,54]. In a study to determine the practicality of using Douglas-fir (Pseudotsuga menziesii) plantations for sheep range, domestic sheep grazed perennial ryegrass in proportion to its availability [32]. PALATABILITY : Perennial ryegrass is palatable to livestock and big game species. Older plants can become tough and unpalatable, especially during hot dry weather [57]. Palatability ratings from selected western states are as follows [9]: Wyoming Montana North Dakota cattle fair fair fair domestic sheep good fair fair horses fair fair fair NUTRITIONAL VALUE : The crude protein content of perennial ryegrass increases with soil nitrogen fertility. Some average values for selected characteristics are as follows [55]: crude protein (%) in vitro digestibility (%) vegetative growth 10.7-18.7 * 88-87 early bloom 10.1-16.9 80-81 heading 13.2 82 mature 9.1 71 * higher values are for higher rates of nitrogen fertilizer The National Academy of Sciences [41] reported various nutritional values for perennial ryegrass; typical values for protein content in hay are as follows: digestible protein (% of dry weight) cattle 5.3 domestic goats 5.6 domestic sheep 4.9 horses 5.7 rabbits 6.1 COVER VALUE : Cover values in North Dakota are rated as poor for mule deer, white-tailed deer, and pronghorn; and fair for upland game birds and waterfowl [9]. VALUE FOR REHABILITATION OF DISTURBED SITES : Perennial ryegrass grows rapidly and is easily established; it is often used for stabilization of soils [19,20]. Perennial ryegrass is often seeded in mixtures with slower growing, longer lived species to provide a quick cover [54]. It is hydroseeded on badly eroded mine spoils in Virginia and Tennesee as part of a seed mixture containing annual and perennial grasses, legumes, and native forbs [38]. Streambank stabilization projects in Utah utilized a grass and forb seed mixture that included perennial ryegrass [56]. Perennial ryegrass was successfully seeded with orchardgrass (Dactylis glomerata), white clover (Trifolium repens), annual ryegrass and vetch (Vicia sativa) for soil stabilization and forage production on severely burned riparian areas in southwestern Oregon [19]. Fire often alters the ability of soils to take up water. In a study on soil wettability after wildfire in lodgepole pine (Pinus contorta) stands in Oregon, perennial ryegrass was seeded with tall fescue, white clover, lodgepole pine and ponderosa pine (Pinus ponderosa). Use of a wetting agent had no apparent effect on plant growth, so it is probably not necessary for successful reseeding after fire [11]. A mixture of grasses and legumes, including perennial ryegrass, was planted on an area burned by wildfire in north-central Washington [22]. In Arizona, seedings that included perennial ryegrass had low initial cover values immediately following a wildfire. By the seventh or eighth year, cover values had increased to nearly 3 times the values on unburned control plots, after which there was a slight drop in cover values [35]. OTHER USES AND VALUES : Perennial ryegrass is a popular turf grass, especially in the south where it remains green all winter [14]. Perennial ryegrass can be used as a winter cover or forage crop in warmer climates [14,54,57]. It is used in mixtures with red clover (Trifolium pratense) in rotation with strawberries (Fragaria x annassa), nursery stock, or vegetables. Perennial ryegrass is usually allowed to grow for 3 years, providing soil improvement and sanitation (in addition to silage and hay crops), then is plowed under as green manure [20]. Perennial ryegrass is used for brushland conversion to range. Chamise (Adenostoma fasciculatum) brushlands in California are cleared by disking or burning, and then reseeded. Perennial ryegrass is recommended (as part of a mixture of species) on better sites above 2,000 feet (610 m) elevation and receiving 28 inches (711 mm) or more of annual precipitation [4]. Love and Jones [34] recommended it for coastal areas and at mid- to low elevations (up to 3,000 feet [914 m]). Hardinggrass (Phalaris tuberosa), tall fescue (Festuca arundinacea) and legumes are recommended in mixtures with perennial ryegrass for brushland conversion in certain areas (detailed in [4,42]). Deer use increases on sites undergoing this type of treatment. In general, seeding after prescribed fire in brushlands increases the amount and quality of forage available to big game and livestock [42]. OTHER MANAGEMENT CONSIDERATIONS : Perennial ryegrass was probably the first grass to be cultivated as a pasture grass in Europe. Records of its use in Europe date to 1681. Thomas Jefferson reported perennial ryegrass as a good producer in Virginia as early as 1782 [14,16]. Annual productivity averaged 2.5 kg/sq m, aboveground dry weight [33]. Perennial ryegrass is widely planted for range, pasture, hay and turf. It is one of the more closely studied pasture grasses. There have been numerous studies on management, nutritive value, and genetics. Many cultivars are available, conferring various characteristics of pest and/or disease resistance and particular growth properties [14]. Reaction to grazing: Perennial ryegrass is slower to establish than common ryegrass, but fully developed stands are equal to common ryegrass in production and are more persistent [20]. Establishment is, however, sufficiently rapid to allow grazing at heavy stocking levels as soon as 2 months after seeding [49]. Perennial ryegrass is well suited for use with subterranean clover (Trifolium subterraneum) for sheep pasture grazing in late winter and early spring where soil moisture is adequate for growth [26]. Such pastures can produce up to 4,465 pounds per acre (5,000 kg/ha) of forage if properly fertilized and maintained [44]. A study was conducted in Oregon to determine the practicality of a rotational short-duration grazing system to maximize pasture growth during the winter or allow rationing of forage produced during the previous fall. There was little or no forage accumulation in January and February. The highest cover for perennial ryegrass (measured in May) occurred on study plots grazed in April (rather than earlier in the year) [26]. Perennial ryegrass has a higher percentage of standing crop dry weight with low levels of nitrogen fertilization than with high or no added nitrogen. Production is best when clipped every 3 weeks (as opposed to unclipped, or clipped at 1 or 6 week intervals) [37]. Perennial ryegrass is considered better for pasture than for hay in Alberta [49]. Tiller number decreases immediately after grazing, then increases so that by May (after grazing in April or earlier) plants have 1.5 to 3 times as many tillers as ungrazed controls [26]. In a growth chamber study, the initial reaction of perennial ryegrass to clipping was an immediate regrowth of the damaged leaves, rather than tiller production [18,37]. Range management practices are generally based on how they affect carbohydrate reserves of grasses. For perennial ryegrass, the peak carbohydrate reserves occur just after flowering in late spring and early summer [55]. Maximum levels of carbohydrate reserves do not have to be maintained for proper management, rather, the reserves must not fall below a critical level [60]. The critical level differs with species and cultivars and is probably affected by fertility and season [58]. In growth chambers, perennial ryegrass was unable to use carbohydrate reserves when the reserves fell below 6 percent of dry weight. At 6 percent, reserves were inadequate for support of the existing tiller population and some tillers died [60]. Areas of use: In Utah, perennial ryegrass is used in irrigated pastures, or for dryland use where there is at least 18 inches (460 mm) annual precipitation and the winters are mild [25]. Competition: Where it is planted with long-lived grass and legumes, perennial ryegrass should not make up more than 25 percent of the mixture so that sufficient numbers of the longer lived species can establish. If it is seeded too heavily in mixtures, it may retard the growth of the other species [20,42]. Although perennial ryegrass is usually associated with fertile soils, under low levels of nitrogen it will outyield sheep fescue (Festuca ovina) and mat nardusgrass (Nardus stricta), which are grasses of infertile pastures [6]. The highest levels of production are on soils of medium to high fertility [57]. The practice of seeding grasses on sites managed for conifer regeneration may result in a decrease in the competitive success of the conifer seedlings. In a study on Douglas-fir regeneration, Newton and Cole [43] found that there were proportional decreases in both root and shoot growth, regardless of competitor type. The survival of ponderosa pine (Pinus ponderosa) seedlings was reduced where they were planted in grass mixtures that included perennial ryegrass [5]. The ability of perennial ryegrass to effectively suppress woody species may be an advantage where grasslands are desired management goals. At moderate to high densities, perennial ryegrass reduced the dry weight gain of sugarberry (Celtis laevigata) by up to 84 percent. It is likely that perennial ryegrass could help inhibit growth of sugarberry on grasslands undergoing secondary succession [53]. In a study of the effects of perennial grasses on annual weeds, perennial ryegrass was least able to suppress annual weeds. It is likely, therefore, that perennial ryegrass may not be the best choice for rehabilitation of degraded pasture and range that is subject to invasion by weedy annuals [5]. The use of introduced species for soil stabilization and rangeland conversion is becoming more questionable because the effect of such species on the community structure of native plants is still poorly understood. Management considerations must take into account both the benefits of erosion control, shrub control and the reduction of shrub competition with conifers, and the negative aspects of competition for space and soil moisture with native herbs and shrubs [19]. Perennial ryegrass has negative effects on natural regeneration of chaparral because it readily outcompetes native herbs, resulting in a reduction of wildflowers. In most cases, natural regeneration after fire may be sufficient without artificial seedings, and has the added benefit of costing nothing [29]. Perennial ryegrass was well established in all plots 3 years after the plots were sprayed with various treatment of silvex, picloram and 2,4-D. The herbicides in the study gave effective 2-year control of woody plants [44]. Perennial ryegrass does best in fall seedings where winter months are mild, but seeding too late in the fall will increase winter-kill to unacceptable levels. Some cultivars have more rapid establishment than others [14]. Seeding rates for perennial ryegrass are as follows [14,54]: In mixtures: 5-10 pounds per acre (5.5-11 kg/ha) 4.5-5.4 pounds per acre (5-6 kg/ha) with legume 8 -10 pounds per acre (9-11 kg/ha) with cereal 29 pounds per acre (33 kg/ha) for erosion control 219-348 pounds per acre (245-39 kg/ha) for lawns In pure stands: 14-25 pounds per acre (16-28 kg/ha) Perennial ryegrass yields from pure stands grown in western Washington average from 4.02 to 4.96 tons per acre (9.01-11.12 t/ha) [45]. Diseases and Pests: Crown rust (Puccinia coronata) may severely reduce forage value in wet areas. Other fungal infections include brown rust (Puccinia dispersa), and red thread (Corticum fuciforme). Occasional attacks by Helminthosporum species also occur. Ergot (Claviceps purpurea) and blind-seed disease (Phialea temulenta) reduce seed yield and quality [14]. Leaf blotch (Helminthosporium spiciferum), ergot and blind seed disease can be substantially controlled by burning perennial ryegrass fields in the spring [21].


SPECIES: Lolium perenne
GENERAL BOTANICAL CHARACTERISTICS : Perennial ryegrass is an introduced, cool-season bunchgrass that grows up to 35 inches (90 cm) tall. It has erect culms and short rhizomes. Perennial ryegrass does not have a creeping growth habit [14,46]. It is generally short-lived (2 to 3 years) [54]. Perennial ryegrass forms vesicular-arbuscular endomycorrhizal associations [2]. RAUNKIAER LIFE FORM : Hemicryptophyte Geophyte REGENERATION PROCESSES : Perennial ryegrass is considered self-incompatible [14]. The seeds are relatively large (0.00027 ounce [7.5 mg]), with no innate dormancy. There are 247,000 to 330,000 seeds per pound [7,34]. The seeds tolerate a wide range of diurnal temperature fluctuation, and germinate in either light or darkness [18]. Casterline Seeds [7] recommended stratification at 47 degrees Fahrenheit (8 deg C) for 5 days before planting. This is not consistent with most authors, who do not recognize a need for stratification. Perennial ryegrass seeds will germinate as soon as moisture conditions permit, regardless of cold treatment [18,50]. Seedbanks of perennial ryegrass are limited and transient; even where perennial ryegrass is a major component of pastures in the Netherlands, it ranks seventh among grasses in numbers of viable seeds and does not accumulate reserves of seeds [18,52]. Schafer and Chilcote [62] determined that the largest decrease in buried seed is due to germination. This type of transient seedbanking is related to exploitation of grasslands that are subject to seasonally predictable drought damage, such as those of mediterranean climates. The lack of a persistent seedbank explains the tendency of perennial ryegrass to be replaced by native grasses with persistent seedbanks, especially in the more northerly latitudes [50]. Along roadsides and in disturbed habitats in the United Kingdom, perennial ryegrass will reproduce well from seed. In neighboring lawns or pastures it may be entirely dependent on vegetative reproduction (probably because the flowering stems are removed before seed production can occur) [18]. The success of self-seeding for stand maintenance in the United States would appear to depend on the ability of seedlings to establish well before frost. Established plants are fairly winter hardy, but since they are short-lived, recruitment from seed would be important for stand persistence [18,49,57]. SITE CHARACTERISTICS : Perennial ryegrass is adapted to a wide range of soil types and drainage conditions and can be grown successfully on earth structures such as dams and dikes, in grass waterways, and in flood channels [14,20,57]. It does not thrive where there are extended periods of low temperatures or drought. Perennial ryegrass will do well in areas that are too wet for other grasses, and short periods of flooding will not severely reduce good stands [14,49,57]. Josselyn and others [63] listed perennial ryegrass as a facultative wetland species (it occurs at 34 to 66 percent frequency on wetland sites in California). Elevation occurrence data from selected western states are as follows [9]: feet meters Utah 3,100-5,100 945-1,555 Colorado 5,000-6,500 1,524-1,981 Wyoming 3,500-6,200 1,067-1,890 Montana 3,200-7,200 975-2,195 SUCCESSIONAL STATUS : Perennial ryegrass is an good competitor and outcompetes other grasses both above and below the ground [10]. Colonization of disturbed areas and adjacent areas can take place by seed dispersal [50]. Perennial ryegrass is probably not shade tolerant; photosynthetic capacity of leaf bases decreases when they are shaded [64] SEASONAL DEVELOPMENT : Perennial ryegrass begins growth early in spring. Peak biomass occurs during cool moist conditions in spring and again in autumn [18]. Flowering occurs from April or May to August, depending on environmental conditions [14,46]. Seeds are released in late spring and summer and germination takes place from August to September or as soon as moisture conditions allow [18,50]. Anthesis dates from selected western states are as follows [9]: Colorado June-August Wyoming June-July Montana May-July North Dakota June-July In the southern states, perennial ryegrass will remain green through the winter [14,20]. In a study of climatic variation in the rate of leaf expansion, Cooper [8] concludes that Mediterranean populations can expand in leaf area more rapidly in winter than continental populations. Maritime populations of perennial ryegrass are intermediate. The differences appear to be dependent on temperature, perhaps due to past climatic selection. Populations in Mediterranean climates are adapted to mild, moist winters and can grow year-round, but populations in continental climates are winter dormant. The peak stem carbohydrate reserve levels occur in early summer, just after flowering begins, dropping off through summer to a low in October. This is in contrast to many other grasses that have two peaks of carbohydrate reserves, one in early spring which is depleted by flowering, then replenished by late summer. Apparently, perennial ryegrass is more efficient at maintaining carbohydrate reserves through the flowering period [55].


SPECIES: Lolium perenne
FIRE ECOLOGY OR ADAPTATIONS : As with most perennial grasses, perennial ryegrass is well adapted to fire. It is top-killed and will sprout quickly from the rhizome. Fire is beneficial to grass swards; by removing litter, it allows more light to penetrate to the leaf bases and new tillers [59]. FIRE REGIMES : Find fire regime information for the plant communities in which this species may occur by entering the species name in the FEIS home page under "Find Fire Regimes". POSTFIRE REGENERATION STRATEGY : Tussock graminoid Ground residual colonizer (on-site, initial community) Secondary colonizer - off-site seed


SPECIES: Lolium perenne
IMMEDIATE FIRE EFFECT ON PLANT : Fire top-kills perennial ryegrass; high-severity fire can kill the rhizomes [20,21]. DISCUSSION AND QUALIFICATION OF FIRE EFFECT : NO-ENTRY PLANT RESPONSE TO FIRE : Fire stimulates the production of reproductive tillers in perennial ryegrass [14]. When field burning was initiated on seed fields in Oregon, seed yields tripled [21]. DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : NO-ENTRY FIRE MANAGEMENT CONSIDERATIONS : Fields of perennial ryegrass grown for seed are usually burned to control blind-seed disease, remove crop residues, improve herbicide effectiveness, and stimulate reproductive tiller initiation. For effective burning, it is important to ensure that crop residues are fairly evenly distributed, since hot spots can be lethal to underground rhizomes [14,20].

References for species: Lolium perenne

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