Perennial Ryegrasses for Turf

Many Uses

• Perennial ryegrass was first released for use as a turf grass in the early 1960s. The grass quickly became a common choice for turf grass throughout the Pacific Northwest and British Columbia. In the southern United States, perennial ryegrass became the grass of choice for over-seeding with warm-season grasses because of its excellent heat tolerance, compared to other cool-season grass varieties. Prior to its popularity as a turf grass selection, it was used widely as an animal forage for over 300 years. The grass establishes rapidly, but it does have moderate- to high-maintenance requirements.

Benefits

• It develops a large, diverse root system and spreads slowly through tillers. Perennial ryegrass can tolerate soil compaction well. The grass grows in clumps and does not develop an overabundance of thatch, except on sandy substrate. Its ability to quickly germinate helps to prevent weeds from occurring in the turf. The grass is often mixed with Kentucky bluegrass when used as a turf for high-traffic areas. The grass does not require excessive water to look its best. During the height of summer, watering the perennial ryegrass one to three times per week will suffice and keep the grass green.

Considerations

• Perennial ryegrass does not tolerate excessive drought well and will begin to die out in areas. Once irrigation has been re-established, the grass will regrow into unattractive clumps and require reseeding to again develop into a lush turf. Perennial ryegrass also requires higher applications of nitrogen per year than other varieties. Depending on the region, the perennial ryegrass will require 4 to 8 lbs. of nitrogen per 1,000 square feet of garden space, according to Oregon State University's website. If the grass does not receive adequate nitrogen, the growth will become thin and unattractive. Over-application of nitrogen can cause the grass to grow too quickly.

Warnings

• In areas that receive excessive snowfall that often persists, perennial ryegrass can suffer pink and grey snow mold. The mold causes excessive damage to the grass. Fungicides can control the snow molds. The grass can also suffer from fusarium patch and leafspot. A turf with perennial ryegrass looks its best when mowed at 1 to 2 inches in height. Some varieties of perennial ryegrass will not tolerate being cut lower and will begin to thin out. Once the grass becomes thin, other grass types or weeds can invade and the grass will also develop spots of unsightly moss growth.