Lolium perenne, common name perennial ryegrass or English ryegrass or winter ryegrass, is a grass from the family Poaceae. It is native to Europe, Asia and northern Africa, but is widely cultivated and naturalised around the world.
The plant is a low-growing, tufted, hairless grass, with a bunching (or tillering) growth habit. The leaves are dark green, smooth and glossy on the lower surface, with untoothed parallel sides and prominent parallel veins on the upper surface. The leaves are folded lengthwise in bud (unlike the rolled leaves of Italian ryegrass, Lolium multiflorum) with a strong central keel, giving a flattened appearance. The ligule is very short and truncate, often difficult to see, and small white auricles grip the stem at the base of the leaf blade. Leaf sheaths at the base are usually tinged pink and hairless. Stems grow up to 90 cm. It has auricles.
The inflorescence is unbranched, with spikelets on alternating sides edgeways-on to the stem. Each spikelet has only a single glume, on the side away from the stem, and between 4 and 14 Florets without awns, unlike Italian ryegrass. The anthers are pale yellow, and the plant flowers from May to November. Perennial ryegrass has a fibrous root system, with thick main roots and thinner lateral branches. Roots are usually arbuscular mycorrhizal.
Cultivation and uses
||The examples and perspective in this section may not represent a worldwide view of the subject. (May 2011)|
Perennial ryegrass is an important pasture and forage plant, and is used in many pasture seed mixes. In fertile soil it produces a high grass yield, and in Britain and Ireland is frequently sown for short-term ley grassland, often with red or white clover (Trifolium).
In Britain, it is also used as an indicator of non-species rich grassland, as it out-competes the more rare plants and grasses, especially in fertile soils. Agri-environment scheme such as the Countryside Stewardship Scheme, Environmentally Sensitive Areas Scheme, and Environmental Stewardship give funding to species rich grasslands that does not have an abundance of ryegrass.
Selected seed mixes are used extensively for sports pitches, especially winter sports in temperate climates, because of its wear resistance and its ability to regenerate.
It is commonly used in the southwest United States to overseed winter lawns. Bermudagrass is a typical summertime grass in states like Arizona, since it is able to withstand the high temperatures. However, Bermudagrass goes dormant during the cooler winter months. Rather than have brown lawns, many homeowners, public areas, and golf courses overseed these lawns with Perennial Ryegrass in early- to mid- September.
Turf-type perennial ryegrass can be grown as a permanent home lawn in the US and typically found as part of a mix with fine fescue and Kentucky bluegrass. However, its adaptation range is limited to areas with moderate winters and mild summers. Full sun to light shade, good yearly rainfall, and proper fertilization are the key to a successful perennial ryegrass lawn.
Perennial ryegrass forms a very dense, dark green, fine bladed turf with the proper maintenance, and it can be successfully grown as a permanent lawn in the Pacific Northwest and costal areas in California. In the East, from North Carolina to Southern New England.
Yearly overseeding might be needed to replace damaged grass caused by excessive heat during the summer. Maximum daytime temperature should not regularly reach 90 °F (32 °C). Night time temperatures should hover around 14–17 °C (57–63 °F). Avoid planting in arid areas if irrigation is not available, or places where extreme temperatures are the norm.
Italian ryegrass, Lolium multiflorum, differs in the fact that each scale in the spikelet has a long bristle at the top. Its stem is also round rather than folded.
- BSBI Description retrieved 10 December 2010.
- Readers Digest Nature Lovers Library Field Guide To Wild Flowers Of Britain, 1998, page 416
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