Scientific: Lolium perenne
Common: perennial rye grass
Family: Poaceae
Origin: Europe, temperate Asia, and North Africa.

Pronounciation: Lo- LIE-um per-EN-knee

Hardiness zones
All (dependingg on use)
USDA All (depending on use)

Landscape Use: Used primarily as an overseeded cool season turf grass in Phoenix and other areas at lower desert elevation across the Southwest.

Form & Character: Soft, refined, yet not delicate.

Growth Habit: This C3 grass has a graminoid growth habit as a bunch grass, low and matting if regularly clipped. If not, the can grow to heights of 1 foot in a bunch-like, non-spreading manner.

Foliage/texture: Medium bright green grass leaves that are folded in the bud, leaf margins are parallel, and abaxial leaf surface is glaborus, leaf blade tapers to a tip. The foliar collar usually has outgrowths (auricles) that clasp the stem; fine texture.

Flowers & fruits: Flowers are spike like from 2 to 12 inches tall. Floral lemmas are awn-less in contract to annaul rye grass. Floral spikelets each contain about 3 to 10 florets.

Seasonal color: None

Temperature: Cold tolerant (will take frost and light freezes), but heat sensitive especially as air temperatures rise above 90oF.

Light: During fall to winter and spring best grown in filtered shade to full sun.

Soil: Well-drained best

Watering: Should be watered regularly except during periods of heavy winter rains.

Pruning: Mow frequently when actively growing. Finished mow height should range from 5/8 inch to 2 inches in height. Mow once grass height reaches 2 to 3 inches depending on the intensity of turf use.

Propagation: Seed; there are around 250,000 seed per pound. Sow perennial rye grass heavily as 1) this is a bunch grass and 2) birds love to eat the seed even if you apply a mulch cover over the seed to protect it and keep the underlying conditions moist for germination.

Disease and pests: Fungal diseases rhizoctonia and Pythium. Because it is not cultured as a perennial lawn in Phoenix, disease and pest pressures on overseed perennial rye grass turf are minimal.

Additional comments: Domesticated perennial ryegrass for turf applications has been heavily bred for a short, matted habit of growth since 1961. Perennial ryegrass is a great utility grass that works well alone or in mixtures with other species. As a winter lawn in Phoenix, perennial rye grass seed is typically broadcast over closely-cropped (scalped) summer turf grass species such as Cynodon dactylon (Bermuda grass) during October. Once established, perennial rye grass will service well until the following May. In Phoenix, transition of a winter lawn to a summer lawn during late spring can be difficult. Perennial rye grass tolerates moderate foot traffic.

There are many named cultivated varieties of Lolium perenne of improved environmental stress and disease tolerance. Perennial rye grass is also an important forage for cattle livestock and sheep and is grown for silage and hay.