Tall fescue (Festuca arundinacea) and perennial rye (Lolium perenne) are both cool season grasses commonly grown in areas with cold winters and moderate summers. Both grasses have certain similarities, such as their intolerance to extreme cold, clumping or bunch-like growth habits (due to which they are often referred to as bunch grasses) and ability to withstand some amounts of traffic. However, their differences enable gardeners to select one over the other, according to their climate and growing requirements.
Tall fescue has flat, broad, dark green leaf blades with visible veins. The leaves are shiny underneath, with serrated edges. It has a coarse texture and deep roots. Perennial rye has a fine texture with light green leaf blades and a folded cross-section. It has a shiny underside and serrated leaf blade tips.
Originally used as pasture grass, tall fescue is now grown in some high-traffic areas such as schools and athletic courses, because it has moderate wear-tolerance. Perennial ryegrass, on the other hand, withstands heavy traffic areas such as golf courses, athletic parks, schools and homes. It also grows and spreads quickly, which is why gardeners also grow it temporarily over a spot to provide a quick green cover, while a slower but permanent grass germinates.
Tall fescue in thrives in well-drained, clay soils in transition zones (areas in the central U.S. that lie between cool and warm season grasses), or areas that include Maryland, Georgia, parts of Nebraska and Kansas. Perennial ryegrass is best adapted to coastal regions, but grows easily in almost all northern states. However, it becomes dormant in the winter in states such as Montana, Minnesota, Wisconsin and North Dakota, and may even die there.
Tall fescue is more drought-resistant than perennial ryegrass because of its deeply embedded roots. It grows in full sunlight to partial shade, but cannot withstand extreme cold. Perennial rye tolerates full sun as well, but lesser shade than tall fescue. It has a low tolerance to extreme cold and drought. According to UC IPM Online, perennial ryegrass has the highest traffic- and wear-tolerance of any of the cool season grasses.
Diseases and Pests
Although tall fescue is moderately disease-tolerant, it is highly susceptible to fusarium blight, which damages young grasses or lawns planted in the spring. Brown patch and leaf spot damage older fescue lawns. White grubs, cutworms and armyworms are pests that damage tall fescue lawns. Perennial ryegrass is susceptible to ergot, brown blight, leaf spots, snow molds and powdery mildew. Pests such as grubs and Argentine stem weevil cause perennial ryegrass problems.
Two of the oldest varieties of tall fescue are Alta and Kentucky-31. Currently, it has more than 60 varieties, out of which Hound Dog, Falcon, Rebel, Olympic, Adventure, Fawn and Goar are a few common ones. Perennial Rye has over 200 varieties available, including blends such as Professional Select.