Lolium multiflorum (Italian ryegrass)

Lolium multiflorum

Photo courtesy Joseph DiTomaso

Lolium multiflorum (Italian ryegrass) is an annual or biennial grass (family Poaceae) found throughout California except in the Great Basin and deserts. Italian ryegrass prefers areas with fertile, well-drained soils, including roadsides, fields, orchards and vineyards. It readily hybridizes with perennial ryegrass (Lolium perenne), and hybrids may exhibit a range of characteristics from both species. Italian ryegrass is commonly cultivated for erosion control, pasture forage, and turf, but has escaped cultivation in many areas. Italian ryegrass is currently very widespread.

Jepson Manual, 2nd Edition: Festuca perennis

Cal-IPC Inventory rating: Moderate

Cal-IPC Resources on Lolium multiflorum

• California Invasive Plant Inventory Assessment Form (pdf) - Information gathered by Cal-IPC on the impacts, rate of spread, and distribution of invasive plants in California. Does not include management information.
• Cal-IPC News - Articles from our quarterly newsletter. Each issue is available as a pdf. List of articles on Lolium multiflorum.
• Cal-IPC Symposium Proceedings - Presentations and papers from our annual Symposium. List of articles on Lolium multiflorum.
• Weed Worker's Handbook (pdf) - Includes reproduction factors and treatment options.

Cal-IPC News Articles

• Martus, C. and C. Schneider (2004). Lessons learned after the San Diego County fires. Cal-IPC News. 11: 8-9.

Cal-IPC Symposium Proceedings

• Carey, C. and S. C. Hart (2011). Alteration of nitrogen cycling processes by exotic annuals in a California grassland. Cal-IPC 2011 Symposium. Tahoe City, CA, California Invasive Plant Council.
• Quinn, L., B. Davis, et al. (2006). Does horse manure harbor invasive plants? Cal-IPC Symposium. Rohnert Park, CA.
• Clines, J., J. DiTomaso, et al. (2004). Grasses working group. California Invasive Plant Council Symposium 2004. Ventura, CA.
• Weiss, S. B. (2003). Nitrogen deposition impacts on a nutrient-poor grassland ecosystem: Conservation, management and restoration. California Invasive Plant Council Symposium 2003. Kings Beach, CA.
• Thomsen, C. D., W. A. Williams, et al. (1996). Yellow starthistle management with grazing, mowing, and competitive plantings. California Exotic Pest Plant Council Symposium '96. San Diego, CA.
• Morey, S. C. and K. E. Shaffer (1995). Exotic plant considerations in the wake of a wildland fire. California Exotic Pest Plant Council Symposium '95. M. Kelly, J. Lovich and J. Randall. Pacific Grove, CA.
• Minnich, R. A. (1994). Effects of exotic plants on three California ecosystems. California Exotic Pest Plant Symposium '94. Sacramento, CA.

Other Resources on Lolium multiflorum

• USDA PLANTS database - Federal database with information on identification and distribution, and links to websites in individual states.
• Jepson Online Interchange for California Flora - Information on taxonomy, biology, and distribution from the UC Berkeley Jepson Herbarium.
• CalFlora - Distribution information by county based on submitted observations and herbarium specimens.
• The Nature Conservancy Management Summary - Information compiled by TNC land managers. Photos included for some species.
• CalPhotos - Images of plants taken mostly in California.
• Natural Resource Projects Inventory - State database with information on resource management projects throughout California. Query by the species of interest.

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