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Aug 162012

Perennial ryegrass (Lolium perenne) is a bunch-type lawn grass that is commonly used in grass mixtures with Kentucky bluegrass (Poa pratensis) on home lawns and sports fields. It is very similar in color and appearance to Kentucky bluegrass.

Perennial Ryegrass

A. Pointed leaf tip of Perennial ryegrass, and B. Glossy bottom of leaf and veiny leaf upper surface. (Photo courtesy: A.J. Turgeon, Penn State University)

The leaves of perennial ryegrass do not have the boat-shaped leaf tip like Kentucky bluegrass, instead have a pointed tip with veins on the top side of the leaves that are very conspicuous. More identifying characteristics can be found here. The veiny leaves make perennial ryegrass difficult to mow especially if mower blades are not kept sharp. This leaf characteristic is also what gives perennial ryegrass the traffic tolerance for use on sports fields.

Perennial ryegrass is not as cold hardy as Kentucky bluegrass and is more prone to winter kill than Kentucky bluegrass. Perennial ryegrass is considered a short-lived perennial because of its lack of cold tolerance and it is not recommended for higher elevations of Idaho, but will do very well along the lower Snake River plains.

Perennial ryegrass germinates from seed considerably faster than Kentucky bluegrass and can overwhelm the other grasses in a mixture if there is too high of a percentage (over 20%). Perennial ryegrass will not fill in bare or damaged areas as quickly due to its bunch-type growth habit. However, an advantage is it does not form thatch due to its lack of rhizomes. Perennial ryegrass is slightly more shade tolerant than Kentucky bluegrass, but may thin out in shaded areas over time due to its lack of storage organs. It is also fairly drought resistant since it can develop a deep root system

Perennial ryegrass requires medium to high cultural practices and should be mowed between 2 to 3 inches. Remember to keep mower blades sharp to cut through the tough leaves. Fertility and irrigation requirements are similar to those of Kentucky bluegrass.

Sod is not available as pure perennial ryegrass, but many sod growers use perennial ryegrass in a mix with Kentucky bluegrass. Establishment of perennial ryegrass from seed is relatively easy due to its very quick germination rate. Seed at rates of 6 to 8 lbs per 1000 ft². As with Kentucky bluegrass, many good quality varieties are available at garden centers. Avoid selecting grass mixtures with annual bluegrass, as this grass produces a poor quality turf over time and should be used for quick, emergency use areas only to prevent soil from eroding. Make sure and select ‘named’ varieties.

 August 16, 2012