All You Need to Know About Perennial Ryegrass

Rye grass
Perennial ryegrass is widely used throughout the United States, but the way it's used differs from region to region. This hard-working grass is valued for its fast germination rate and quick establishment, which makes it a valuable component in permanent and temporary lawns. Under proper growing conditions in suitable regions, perennial ryegrass forms a lush, fine-bladed lawn that maintains its color into winter. Depending on where you live and your immediate lawn goals, perennial ryegrass may offer just what you need.


Perennial Ryegrass at a Glance
  • Cool-season lawn grass
  • Fast germination and seedling growth
  • Used for permanent and temporary lawns
  • Good cold tolerance
  • Heat and drought tolerance varies by variety
  • Withstands light shade

Perennial Ryegrass Basics
Perennial ryegrasses are used throughout the United States as turf grasses and as high-quality pasture grasses for livestock. Despite its agricultural uses, perennial ryegrass isn't related the rye plant that produces cereal grain. Perennial ryegrass is related to the turf grass known as annual ryegrass, but these two plants differ, too. As the name suggests, annual ryegrass is a short-lived grass used to provide quick color, short-term erosion control or temporary stability for a single season. Turf-type perennial ryegrass is also used in those ways, but it establishes a permanent lawn that comes back year after year in proper climates.

Perennial ryegrass is a cool-season grass, meaning it peaks in growth during cool seasons, from fall through spring. Like many common turf grasses used for permanent northern lawns in the U.S., perennial ryegrass is native to Europe and Asia.1 Though it's not as cold-hardy as Kentucky bluegrass or tall fescue, perennial ryegrass flourishes where summers are moderate and winters are cool. In the cool, humid Pacific Northwest, it has become one of the region's most widely used permanent lawn grasses, on its own and mixed with other cool-season grasses.2

Even though perennial ryegrass is naturally suited to more northern climates, southern lawn owners use it extensively as well. Warm-season grasses used in the south and west, such as Bermudagrass, go dormant and turn brown during cool winter months. Perennial ryegrass is often seeded over existing warm-season lawns in fall, just as you might overseed a thinning northern lawn as part of your fall lawn tasks. Fast-germinating perennial ryegrass creates a temporary green lawn for winter months, and then dies out when southern heat returns and warm-season grasses turn green again.
Southern Golf Course
Other Characteristics to Consider

Given the proper conditions, perennial ryegrass germinates faster than any other common lawn grass seed.2,3 Once established, however, it spreads slowly. Unlike aggressive Kentucky bluegrass, which spreads by underground stems called rhizomes, perennial ryegrass is a bunch-forming grass. Like tall fescue, it naturally grows in clumps and spreads through vertical shoots known as tillers, rather than spreading by rhizomes or horizontal above-ground stems, known as stolons.

Traditional perennial ryegrass varieties have relatively shallow roots, which historically limited their tolerance for heat and drought compared to tall fescue or deep-rooted warm-season Zoysia grass. However, improved varieties of perennial ryegrass, such as those developed through Pennington-affiliated research and breeding programs, have greater heat and drought tolerance. Water-conserving Pennington Smart Seed Perennial Ryegrass is a drought-tolerant, premium blend of perennial ryegrass varieties that establish quickly to form lush, traffic-tolerant turf that requires up to 30 percent less water year after year than ordinary grass seed. These improved varieties also require less mowing than common perennial or annual ryegrasses do.

All you need to know about Perennial Ryegrass
Perennial ryegrass is also a key component in cool-season grass seed mixes for northern and transition zone lawns and athletic fields. Its fast germination and rapid seedling growth provide these plantings with quick color and stability, allowing slower germinating grasses, such as Kentucky bluegrass, more time to get established. Perennial ryegrass prefers sun, but it will tolerate lightly shaded conditions.

Perennial Ryegrass Lawn Care
The best time to plant cool-season grasses, including perennial ryegrass, is in fall, when cool temperatures and other conditions complement the plant's natural growth. This holds true whether you're seeding a permanent northern lawn or adding winter color for a temporary southern lawn. Likewise, the month-by-month lawn care calendar for perennial ryegrass follows that for other cool-season grasses.

Mow perennial ryegrass to maintain the recommended mowing height of 1 1/2 to 2 1/2 inches. Though this is higher than many warm-season lawn owners are used to, this helps clump-forming perennial ryegrass stay dense and look and perform its best. When planted with Kentucky bluegrass in cool-season lawns, mow perennial ryegrass at the slightly taller 2- to 2 1/2-inch height recommended for Kentucky bluegrass lawns.

Perennial ryegrass has relatively high fertilizer and water needs compared to tall fescue and common warm-season lawn grasses. During periods of heat and low rainfall, and during southern winters, the grass requires frequent irrigation to maintain color. If the grass is allowed to go dormant during short periods of drought, it will recover quickly; however, overseeding may be needed after prolonged drought.2 Pennington's Water Rate Calculator can help you determine the best watering plan for your location and weather.

All-You-Need-to-Know-About-Perennial-Ryegrass
Perennial ryegrass adapts well to a wide variety of soil types and to both acidic and alkaline soils. Soil pH in a range of 5.5 to 7.5 typically supports the best perennial ryegrass growth.4 Testing your lawn's soil every three to four years can help you keep your soil pH and soil nutrients at optimal levels for perennial ryegrass and other grasses present. Your local county extension agent can help with information on kits and care.

When you need a fast-establishing turf grass for northern or southern applications, perennial ryegrass can provide the speed, strength and color you need. Pennington is dedicated to helping you grow the finest lawn possible. With the help of premium grass seed, lawn care products, timely email advice and online resources, your lawn can be everything you hope it will be.

Pennington and Smart Seed are registered trademarks of Pennington Seed, Inc.

Sources:

1. Duble, R.L., “Ryegrass, Temporary Sports Turf for the South," Texas A&M Agrilife Extension.

2. Cook, T., “Perennial Ryegrass Lolium Perenne L.," Oregon State University Department of Horticulture.

3. UC Statewide Integrated Pest Management Program, “Grass Seed Germination Rates," University of California Agriculture & Natural Resources.

4. Hannaway, D., et al., “Perennial Ryegrass," Oregon State University Extension, April 1999.
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