Synonym(s): English rye grass, Perennial Rye Grass
Family: Poaceae (Grass Family)
Duration and Habit: Annual or Perennial Grass
Perennial ryegrass can grow 1 to 2 feet tall and has medium longevity. There are numerous long, narrow, stiff leaves near the base of the plant. The under surfaces of leaves are bright, glossy, and smooth. Perennial ryegrass leaves are usually folded in the bud (but also can be rolled). The flowerhead is 3 to 12 inches (8–30 cm) long. The flower color is yellow. Seedheads are spikes with spikelets growing edgewise to the seedhead stem. The seeds do not have awns.
Native Lookalikes: Currently no information available here yet, or there are no native Texas species that could be confused with Perennial ryegrass.
Ecological Threat: Lolium perenne has a moderate potential impact on native ecosystems (calflora.org).
Biology & Spread: Spring seedings of ryegrass can occur in March, April, or May. Perennial ryegrass may also seed mid- August to early September. Seeding rates will vary with local conditions.
History: Lolium perenne is the predominant forage grass in Europe. It was brought to the United States for the same purpose, forage and lawns. This species is also used for soil stabilization. The tetraploid cultivars are typically used for forage, and the diploid cultivars are used for lawns and conservation plantings. Similarly, Italian ryegrass is used for erosion control plantings.
U.S. Habitat: Lolium perenne grows on roadsides, open fields, crop fields, pastures, orchards, and vineyards. These grasses can thrive in many types of soils, but thrive best on dark rich soils in regions with mild climates. They do not withstand hot, dry weather or extreme cold temperatures. They will stand fairly wet soils that has reasonably good surface drainage. Equally likely to occur in wetlands or non wetlands.
U.S. Nativity: Introduced to U.S.
Native Origin: Europe
U.S. Present: AK, AL, AR, AZ, CA, CO, CT, DC, DE, FL, GA, HI, IA, ID, IL, IN, KS, KY, LA, MA, MD, ME, MI, MN, MO, MS, MT, NC, ND, NE, NH, NJ, NM, NV, NY, OH, OK, OR, PA, RI, SC, SD, TN, TX, UT, VA, VT, WA, WI, WV, WY
Distribution in Texas: Perennial ryegrass is distributed throughout the entire United States.
Italian ryegrass is very similar to perennial ryegrass. It can be an annual or biennial, depending on climate and/or length of growing season. Italian ryegrass can grow from 2 to 3 feet tall. The seeds of this sub-species have awns.
http://plants.usda.gov/core/profile?symbol=lope http://www.calflora.org/cgi-bin/species_query.cgi?where-calrecnum=4946 http://www.missouriplants.com/Grasses/Lolium_perenne_page.html http://www.ipm.ucdavis.edu/PMG/WEEDS/ryegrasses.html
USDA-NRCS. (2002). Plant Fact Sheet: Lolium perenne L. Retrieved from http://plants.usda.gov/core/profile?symbol=lope
Google Search: Lolium perenne
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USDA Plants: Lolium perenne
Invasive Plant Atlas of the United States: Lolium perenne
Bugwood Network Images: Lolium perenne