Page author: Don Knoke
Lolium perenne
English ryegrass, perennial ryegrass

Distribution: Commonly cultivated as a forage plant; escaped and well established in the Pacific Northwest.

Habitat: Old fields, roadsides, and waste places.

Flowers: May - July

Origin: Introduced

Growth Duration: Perennial

Conservation Status: Not of concern


Glabrous, tufted perennial, the hollow culms 3-8 dm. tall, usually with several basal, short, leafy stems.


Sheaths open; auricles developed on most leaves; ligules entire, 0.5-1.5 mm. long; blades 3-4 mm. broad, flat to folded.


Inflorescence a single terminal spike 7-25 cm. long, the spikelets on opposite sides of the continuous rachis to which they are attached edgewise; spikelets 6- to 10-flowered, crowded and spreading to distant and erect; glume 7-10 mm. long, pointed, usually exceeding the lower lemma, the glume next to the rachis lacking except on the terminal floret; lemmas acute, unawned, 5-nerved; paleas subequal to the lemmas, firm, 2-nerved.

Accepted Name:
Lolium perenne L.
Publication: Sp. Pl. 1: 83. 1753.

Synonyms & Misapplications:
Lolium multiflorum Lam. var. ramosum Guss. ex Arcang.
Lolium perenne L. var. cristatum Pers.
Additional Resources:

PNW Herbaria: Specimen records of Lolium perenne in the Consortium of Pacific Northwest Herbaria database.

WA Flora Checklist: Lolium perenne checklist entry.

E-Flora BC: Lolium perenne atlas page.

CalPhotos: Lolium perenne photos.

USDA Plants: Lolium perenne information.

12 photographs:
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