Perennial Ryegrass
Perennial ryegrass may be the best solution you’re looking for, depending on where you reside and your immediate lawn goals. The method that perennial ryegrass is employed varies from region to region within the United States. With its rapid germination rate and quick establishment, this tenacious, fine-bladed grass attracts admirers. It is an appreciated component in permanent northern lawns and southern lawns that need temporary winter color.
Perennial ryegrass is native to southern Europe, North Africa, the Middle East, and eastwards to central Asia. As a beneficial grass species for fodder and grazing cattle, it has been introduced by rootin new areas like North America, South Africa and Australia.
In every state of the U.S.A., perennial ryegrasses are used as pasture grasses for cattle and as turf grasses. In spite of its usage in agriculture, this grass isn’t related to the rye plant that yields cereal grain. Though, it is linked to the annual ryegrass, but these two grasses are different.
Annual ryegrass, as its name implies, is a transient grass which is used to provide quick color, and short-term (like for a season) control of soil erosion. Turf-type perennial ryegrass is utilized in the same ways but it returns year after year in northern regions to establish a permanent lawn.
Due to its great ability to set seed, and its ease of germination and vigor, it easily gets spread from the fields where it is planted to roadsides, footpaths, trackways, sand dunes, wasteland, and river banks. Perennial ryegrass can be regarded as an invasive species that competes with native plants in countries where it has been introduced.
It thrives in regions with temperate summers and cool winters, however, it is not as cold-hardy as Kentucky bluegrass or tall fescue grass. This has become one of the most widely used permanent lawn grasses in the cool and humid Pacific Northwest, both alone and combined with other cool-season grasses.
Perennial ryegrass, whose scientific name is Lolium perenne, has many uses but possibly doesn’t get the credit it should. Kentucky bluegrass is regarded as the ideal lawn grass, fescues are known for their shade and low maintenance, and perennial ryegrass is generally known for its speedy germination and nothing else. But this grass is much more than a nurse grass.
In ideal conditions, it germinates in less than a week (mostly four to seven days) and produces a medium to dark green attractive lawn. Once this grass is established as a mature turf, it has relatively good resistance to wear.
This grass also has excellent striping ability, another feature that makes it attractive to lawn owners. It has a waxy coating on the leaves that creates lawn stripes stand out even more.
Perennial Ryegrass At A Glance
| Scientific (Botanical) Name | Lolium perenne |
| Family | Poaceae |
| Plant type | Perennial, grass |
| Classification | Cool-season grass – |
| Grass Texture | Soft |
| Grass Color | Medium to dark green color |
| Spreads by (or growth habit) | Bunch-forming growth habit |
| Requirements for soil type | Good drainage, high fertility |
| Fertilizer requirements | Moderate |
| Mowing requirements | Moderate |
| Drought Tolerance | Low (summer dormancy in certain areas) |
| Average Mowing height | 2 to 3 inches |
| Uses | Overseeding for quicker color, erosion control, weed suppression for multiple seasons |
| Optimum soil pH range | 5.5 to 7.5 |
| Shade tolerance | Low (prefers full sun) |
| Root system | Shallow |
| Heat tolerance | Low |
| Foot traffic tolerance | High, but poor recuperative ability |
| Maintenance needs | Moderate mowing needs depending on cutting height (lower cutting heights may require more frequent mowing) |
| Germination Rate | Rapid |
| Disease Potential | High (particularly in areas with hot and humid summers) |
| Native Area | Southern Europe, North Africa, the Middle East, and eastwards to central Asia |
What Are The Weaknesses of Perennial Ryegrass?
Perennial Ryegrass Weaknesses
1) Low-Temperature Ceiling
Although perennial ryegrass thrives in cold climates, it has a low-temperature ceiling than other perennial grasses. Beyond this ceiling, its growth rates drastically decrease, sometimes causing the plants to become dormant and die out.
2) Shallow roots
The first 10 centimeters of perennial ryegrass alone contain over 75% of the entire root mass. This is why it is difficult for perennial ryegrass to assess moisture that is present deep in the soil. The primary cause of perennial ryegrass’s reputation for poor persistence in dry environments is its shallow root system.
3) Lower Chances to Postpone Cutting or Grazing
Perennial ryegrass can’t be kept as a standing sward. Therefore, there isn’t much opportunity available to cut high-quality perennial ryegrass once the best time for grazing has passed.
4) Waterlogging
Perennial ryegrass can unquestionably endure brief episodes of waterlogging. However, there is a limit. The lack of oxygen in the root, which results from excessive waterlogging, lowers productivity and may even result in plant death.
5) Poor Growth in summer
Perennial ryegrass cannot always produce a sufficient amount of high-quality feeds during the hot, dry summer months, due to its shallow roots and low-temperature ceilings.
How and When to Plant Perennial Ryegrass?
Ryegrass for Overseeding southern lawns
Perennial ryegrass is widely used by southern lawn owners even though it naturally thrives in northern temperatures. Warm-season grasses, like Bermudagrass, used in the west and south, become dormant and turn brown during the cold winter months.
Southern lawn owners sow perennial ryegrass over their current warm-season lawns in the fall to keep their lawns green throughout winter. When warm-season grasses green up and the summer heat arrive, fast-germinating perennial ryegrass, which had produced a transient green lawn for the winter, dies out and disappears. This grass is a great option for winter overseeding in the southwest, where it is common to maintain green lawns all year.
Additional Perennial Ryegrass Considerations
Perennial ryegrass sprouts more quickly than any other general lawn grass seed, under appropriate conditions. Once it’s established, it spreads gradually. Perennial ryegrass is a bunch-forming grass, as opposed to aggressive Kentucky bluegrass, which grows by subterranean stems (known as rhizomes). Similar to tall fescue, it develops naturally in clumps. It spreads by tillers (vertical shoots) as opposed to rhizomes or stolons (horizontal above-ground stems).
Old varieties of perennial ryegrass have comparatively shallow roots, which generally reduced their ability to withstand drought and heat in comparison to tall fescue or deeply rooted warm-season Zoysia grass. However, newly developed perennial ryegrass varieties have increased resistance to drought and heat.
Once established, these new improved types use up to 30% less water each year than ordinary varieties. In comparison to ordinary perennial ryegrass, they also require less mowing.
Furthermore, perennial ryegrass plays a significant role in the cool-season grass seed blends used for transition zone and northern lawns, and athletic fields. Its quick germination and rapid seedling development offer instant stability and color. Although perennial ryegrass thrives well in the sun, it can also tolerate a little shade.
What Are The Diseases That Can Affect Perennial Ryegrass?
Major diseases that can affect Perennial ryegrass include the following:
Perennial ryegrass is susceptible to various turfgrass diseases, particularly in hot summer weather. Some of these are:
1. Snow Mold
Perennial Ryegrass is susceptible to snow mold. It develops at the margins of a melting snow pile, under the snow, or where moist conditions exist through the winter period.
Its most common symptoms are gray, white, or pinkish colored circular patches of matted down grass.
A treatment with an appropriate fungicide is suggested just before the first snowfall on lawns that are less than a year old or where this disease has been an ongoing problem.
2. Pythium Blight
Various species of the fungus pythium can cause Pythium blight in perennial ryegrass.
Poor air circulation and abundant moisture are some of the conditions that favor Pythium blight. The blight first appears as patches ranging from 1 to 2 inches in diameter.
Affected leaves are at first water-soaked, slimy and soft, and may mat together. These leaves soon shrink and the color of the patch gradually turns brown.
It is possible to control this blight with both fungicides and cultural controls like improving air circulation.
3. Rust
Perennial ryegrass is also sometimes affected by Rust infection and is generally a late summer or early fall disease occurring during prolonged periods of overcast weather.
Rust disease results from the rust spores which are blown to the grass from nearby or distant alternate hosts. This disease will first appear as a light yellow flecking on the grass leaves. Then, these spots develop into reddish-brown pustules.
Fungicide treatments may be required to treat rust disease.
To prevent rust disease from damaging your grass, you should follow steps like:
- Improve the grass air circulation (by frequent mowing on the recommended height)
- Prevent the grass from getting overly wet
- Use adequate amount of nitrogen fertilizer in the soil
4. Dollar spot
Dollar spot disease of perennial ryegrass is a fungal disease and that can occur at any point during the grass’s growing time.
Dollar spot is characterized by the development of small straw-colored spots that occur on the individual leaves and are of size of a silver dollar. On inspecting the infected leaf blades during the early hours when the grass is wet with dew, you can see white thread-like hyphae of the disease-causing fungus.
Dollar spot mostly develop when the soil moisture content is low and the humidity is high. This disease also develops when adequate amounts of fertilizer are not used on soil.
Use of appropriate fungicides is the main treatment method for dollar spot.
Prevention:
- Remove Excessive thatch.
- Appropriate use of fertilizers
- Appropriate watering techniques
5. Brown Patch
Brown patch disease is the most common disease that affects perennial ryegrass lawns. Above 68 degrees Fahrenheit of night temperature and 80 degrees of day temperature may cause this disease. In addition to the temperature, heavy applications of nitrogen fertilizer and humid weather favor the development of this disease.
The most common indication of a brown patch is a ring of brown colored grass around a patch of green grass.
You can avoid this disease by moderate fertilization during summer. In case, the disease is already spread, you can treat it by applying appropriate fungicides.
6. Red Thread
Small blighted areas appear on Perennial ryegrass leaves in early stages of red thread. Leaves become covered with reddish threads of fungal mycelium in the late stages. It affects the leaf, stem, and sheath of the grass, but can kill the whole plant in severe cases.
Conditions such as insufficient nitrogen levels and excessive moisture favor this disease.
To create a stronger perennial ryegrass lawn, and to increase the tolerance of the lawn against drought, disease, and other stresses; you should choose a blend with various different cultivars in one mix.
Perennial Ryegrass Lawn Care Calendar
Like other cool-season grasses, perennial ryegrass grows most actively during the cool seasons of spring and fall. It slows down or turns dormant throughout the summer in permanent northern lawns. Timing your seasonal lawn care tasks according to these natural cycles can help perennial ryegrass maintain its optimum performance and appearance.
Within the widespread growing region of perennial ryegrass, weather conditions can differ considerably, so it’s better to take guidance from a professional for your lawn tasks from year to year. You can also check with your province extension agent regarding typical frost dates and planting times in your area. To maintain a healthy, stunning lawn, you can follow this perennial ryegrass lawn care calendar.
From March to May
Mowing
When your lawn begins to grow, start cutting it. To keep growth thick and attractive, keep perennial ryegrass at a height of 1½ to 2½ inches. To prevent the spread of winter fungal disease, bag the first clippings of the season.
Fertilization and Prevention of Weeds
You should prevent crabgrass, while fertilizing perennial ryegrass lawn in the early spring.
Before soil temperatures hit 55 degrees Fahrenheit and weed seeds begin to germinate, apply a good Crabgrass Preventer.
Avoid its application to areas that have been sown or overseeded within 60 days after seeding.
Seeding and Overseeding
Perennial ryegrass, like other cool-season grasses, germinates best at temperatures from 50°F to 65°F. Next to fall, spring is the optimum season to sow the lawns with Perennial Ryegrass seeds.
Fertilization and Weed Control
In the late spring, when the grass and weeds are in active growth, fertilize your lawn and control the emerged broadleaf weeds with a good weedicide.
Application of weedicide to newly seeded areas should be avoided until you mowed the new grass at least three times. Also for reseeding, you should wait at least three weeks after applying weedicide.
Watering
Irrigate your established perennial ryegrass lawn so that it receives about 1 inch of water per week. To promote deeper root development, thoroughly and deeply water the soil.
From June to August
Mowing
Increase the mowing height of the grass between 3 to 4 inches during periods of heat and low rainfall. And while mowing, never remove more than one-third of the leaf blade at any one time.
Fertilization
Use an appropriate Fertilizer to fertilize your perennial ryegrass lawn.
Watering
Irrigate your established perennial ryegrass lawn so that it receives about 1 to 1¼ inches of water per week, including rainfall.
Pest Control
Insects such as beetles and grubs can harm lawns. Early pest management with appropriate pesticides reduces damage and halts the spread of new pest generations.
Soil Testing
You should test your lawn soil after every three to four years to check its pH and nutrients. The optimum pH range for perennial ryegrass is 5.5 to 7.5. Lime may be required for your lawn in regions with very acidic soil, like parts of the Pacific Northwest, to restore nutrient availability.
From September to November
Mowing
As fall season approaches, gradually reduce mowing height of your grass to 1½ to 2½ inches. You should keep mowing your lawn until growth stops.
Fertilization and Weed Control
Six to eight weeks prior to the first anticipated frost in your area, treat broadleaf weeds and fertilize your established perennial ryegrass lawns.
Seeding and Overseeding
The ideal time to plant perennial ryegrass, like other cool-season grasses, is early fall. Plant perennial ryegrass seed in northern lawns about 45 days prior your area’s first fall frost.
When warm-season grass begins to go dormant and become brown, and when nightly air temperatures fall between 65 and 70 degrees Fahrenheit, you can overseed southern lawns for winter color.
Watering
Gradually reduce watering In northern lawns. Water your lawn so that it receives about 1 inch of water every 10 to 14 days, including rainfall.
Continue routine watering in southern lawns so that perennial ryegrass receives an inch of water per week.
Dethatching and Aeration
When necessary, aerate compacted soil. Perennial ryegrass is a clump-forming grass and produce insignificant thatch.
Leaf Management
Mulch or rake fallen leaves so that your grass enters the winter season free of leaf cover.
From December to February
Maintenance of Southern Lawn
Perennial ryegrass in dormant warm-season lawns should still be mowed and watered on a regular basis
Maintenance of Northern Lawn
Keep the winter debris off of your grass. As ice melts in late winter, flush areas that have been affected by the damage caused by deicing salts or pet urine. Also, maintain your lawn equipment and mowers so that they are ready for spring.
Perennial ryegrass may deliver the speed, color and vigor you want, when you need a turf grass that quickly establishes in northern or southern zones.
References:
1) Ryegrass, Temporary Sports Turf for the South – Texas A&M Agrilife Extension.
https://aggie-horticulture.tamu.edu/plantanswers/turf/publications/ryegrass.html
2) Perennial ryegrass Lolium perenne L. – Oregon State University Department of Horticulture
http://agsci.oregonstate.edu/sites/agscid7/files/horticulture/beaverturf/PerennialRyegrass.pdf
3) Turf Diseases & Pests – University of Kentucky
https://www.uky.edu/Ag/PAT/cat3/cat3g.htm
4) Perennial Ryegrass Grown for Seed – Oregon State University Extension, November 2013
https://catalog.extension.oregonstate.edu/sites/catalog/files/project/pdf/em9086.pdf
5) Grass Seed Germination Rates – University of California Agriculture & Natural Resources
https://ipm.ucanr.edu/TOOLS/TURF/ESTABLISH/germin.html
Recommended Articles:
1) Kentucky Bluegrass: Types, Problems, & How To Plant
2) Bermuda Grass: Its 17 Types, & 5 Common Diseases
3) Zoysia Grass: Types, Problems, And How To Plant & Grow
4) Tall Fescue Grass: Types, Problems, How To Plant & Grow
5) Bentgrass: Types, Diseases, And How To Plant & Grow