Italian Ryegrass

Reg Newman, BC FLNR
Scientific name: 

Lolium multiflorum Lam.

Agronomic Grass
Annual precip. min (mm): 
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Seed size: 
Seeds per kg: 
Typical seeding objectives: 
PR Suitability note: 
Since Italian Ryegrass is an annual, it has suitability for both forage (late fall pasture), and in site rehabilitation mixtures when quick ground cover is needed the first growing season after seeding.
Key considerations: 
Italian ryegrass is a highly suitable choice for a mixture with native species when there is a native plant community objective, because it is unlikely to persist for more than one or two years. It can provide cover while slower growing species become established.
General Description: 

Italian ryegrass is a short-lived, highly tillered, cool season biennial bunchgrass. It is usually grown as an annual forage or a quickly establishing, green ground cover. There are two types of ryegrasses: Italian and Westerwold, both with diploid and tetraploid varieties. Ryegrasses cross-pollinate freely and it is difficult to maintain genetic purity. Often they form a mixture of perennial and annual species.

Italian ryegrass is a bunchgrass that grows very dense, fibrous, shallow roots that do not tolerate drought. Vegetative growth can be vigorous with stand height reaching to 40 cm (16 in.), which can become thick and often lodged. Leaves are long, tapered, about 10 mm wide, keeled, and dark green. One side is glossy and the edges are smooth.

Seed heads develop on stems up to 100 cm (39 in.) long as spikes up to 25 cm (10 in.) long with alternately arranged spikelets that are placed edgewise to the rachis. Spikelets form 10 to 20 flowers that cross-pollinate. Seeds shatter very easily.

Italian ryegrass originates from northern Italy. Westerwold ryegrass was developed in the Netherlands from Italian ryegrass, and can set seed in the year of sowing.
Habitat and climate: 
Well adapted to mild, moist climates.
Italian ryegrass is used for hay and irrigated or intensively managed pasture. It is also used extensively for quick ground cover in post-wildfire rehabilitation and other rehabilitation contexts. Westerwold ryegrass is used for silage, hay, or seed, but winter survival depends on variety, conditions, and management. Italian ryegrass is used as a lure crop for waterfowl and is intercropped with corn in southern British Columbia.
Optimal time of grazing use: 
Throughout the season and a good option for extending grazing into late fall and early winter.
Recovery after use (rating): 
Recovery after use: 
Excellent tolerance to grazing and quick recovery to use. Allow 3 to 5 weeks for regrowth. Vegetative material is soft and easily damaged by trampling. Although continuous grazing is acceptable, trampling damage can be reduced with managed or rotational grazing.
Forage yield: 
Italian ryegrass yielded 8,960 kg/ha (8,000 lb/acre) over 2 harvest operations in 1 year (at Melfort, SK., 1998-2000). Westerwold ryegrass yielded 10,400 kg/ha (9,300 lb/acre) at the same research site. Single-year yields from three irrigated sites in the Cariboo and Chilcotin ranged from 2,760 to 5,610 kg/ha (2,464 and 5,008 lb/acre). A non-irrigated site in the same region produced 487 kg/ha (435 lb/acre).
Palatability/Nutritional Value: 
Highly palatable and highly digestible. Fall regrowth showed crude protein 17 to 23% (dependent on sampling time and variety, at Melfort, 1992).
Longevity (rating): 
Will only live 1 to 2 years.
Persistence (rating): 
Competitiveness (rating): 
Highly competitive in the first year of growth.
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Drought tolerance (rating): 
Winter hardiness (rating): 
Winter hardiness: 
Winter severity determines whether plants survive for a second year.
Soil texture preference: 
Grows best on fertile, well-drained soils but is adapted to a wide range of soil types and textures.
Flooding tolerance (rating): 
Flooding tolerance: 
Good tolerance to excess moisture and short period of flooding.
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Acidity tolerance (rating): 
Acidity tolerance : 
Italian ryegrass has good tolerance to acidity.
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Ease of establishment: 
Italian ryegrasses are easy to establish. Seed in mid- to late-May or if concerned about weed pressure, delay seeding until mid-June. Responds well to fertilizer applications (especially N and P). If broadcasting N, apply before seeding or after plant is at the 2- to 3-leaf stage. Functions very well as a nurse crop while establishing other slower growing forage crops.
Suggested mixtures: 
Italian ryegrasses can be seeded in mixtures, although they should be seeded at a low rate to allow establishment of slower to establish perennials.