Perennial Ryegrass


Lolium perenne L.
Perennial ryegrass is a short-lived, perennial, cool season bunchgrass. It is closely related to Italian ryegrass, but is smaller, has folded rather than rolled leaves, and lacks awns. Perennial ryegrass produces a shallow, fibrous root system, with the majority of roots in the upper 15 cm (6 in.) of soil. It tillers freely and produces a dense sod.
Perennial ryegrass produces a dense cover of low-growing leaves, and stems that are up to 60 cm (24 in.) long with a slender spike up to 30 cm (12 in.) long. Leaves are dark green, narrow, hairless, keel-shaped, and folded when young. Lower surface is glossy and smooth, while upper surface is veined and duller coloured.
There are diploid and tetraploid genetic types (double chromosome types often associated with more vigorous growth but less hardiness) with a tremendous variation in seed size both between and within genetic types.