Ornamental · Poaceae
Perennial Ryegrass
Lolium perenne
Sow it and it's up in days, giving you fast, fine-bladed, hard-wearing turf that greens a lawn in a fortnight.
Full sun
Every 2–7 days
14–21 days
USDA 3–7
Overview
Perennial ryegrass is a cool-season grass prized for how fast it comes up. Seed it and the first blades show in 3 to 7 days, quicker than any other common lawn grass, which is why it goes into so many seed mixes and quick-fix patches. The blades are fine to medium and a glossy dark green, and the turf takes hard wear, so it ends up on plenty of sports fields and family lawns.
It grows in clumps rather than creeping outward. As a bunch grass it has no rhizomes or stolons, so each plant stays put and a worn patch will not close on its own. Many people pair it with Kentucky bluegrass for that reason, letting the bluegrass spread by rhizome to fill gaps while the ryegrass brings speed and toughness.
It runs cool and likes steady moisture, holding green from a deep cold of -20°F (-29°C) up to summer heat near 95°F (35°C), though it sulks in real drought. Across the South it does double duty as a winter overseed, sown over dormant warm-season lawns to keep them green until spring.
Care
The short version: full sun, steady moisture, and regular mowing to about 1.5 to 2.5 inches (4 to 6 cm). Feed in spring and fall, keep nitrogen light in the summer heat, and reseed thin spots since the grass won't fill them on its own.
Light
Perennial ryegrass does best in full sun but takes some partial shade. The more sun it gets, the denser and tougher the turf, while a deeply shaded spot leaves it thin and weak.
Water
Keep a new seedbed consistently moist so it sprouts in 3 to 7 days, watering lightly and often until the grass is up. Established turf wants moderate to high water and slips fast in drought, so don't let it dry out for long.
Soil
Plant in fertile, moist, well-drained soil. A pH of 6.0 to 7.0 suits it well, and ground that drains freely while still holding moisture keeps the stand healthy.
Temperature
As a cool-season grass it handles a wide range, from about -20°F (-29°C) in winter up to roughly 95°F (35°C) in summer. It grows hardest in the cool of spring and fall and tends to slow and struggle through real summer heat.
Humidity
Ordinary outdoor humidity is fine, so there's no number to hit. Long spells of leaf wetness are the real risk, since damp blades in warm weather open the door to gray leaf spot.
Feeding
Feed with a balanced turf fertilizer in spring and fall, when the grass is growing hardest. Go light on nitrogen in late spring and summer, since a flush of soft growth in the heat invites gray leaf spot.
Pruning
Mow on a regular schedule to about 1.5 to 2.5 inches (4 to 6 cm). If gray leaf spot turns up, bag and remove the clippings so you aren't spreading the fungus around the lawn.
Repotting
none
Size & spacing
The mowed blades stand only about 2 inches (5 cm) tall, and each clump spreads to roughly 6 to 12 inches (15 to 30 cm). Since it grows in bunches without runners, sow seed thickly and evenly so the clumps knit into solid turf.
When to plant
Perennial ryegrass is a cool-season grass, so it wants to go down when the weather is mild, not hot. Sow or overseed in early fall, or in spring in cool regions, and across the South lay it over a dormant warm-season lawn in fall to carry green through the winter.
Northern hemisphere
Southern hemisphere
Typical months for a temperate climate: start earlier in warm zones, later where spring frosts linger.
- Plant: Seed or overseed in early fall (or spring) in cool-season regions; standard winter overseed for dormant warm-season lawns in the South.
- Harvest: Establishes uniform turf within about 2 weeks under ideal conditions.
Hardiness
USDA hardiness zones: 3–7
Temperature: down to -40°C
Troubleshooting
Most ryegrass trouble shows up as patches in the turf, and the weather usually tells you which problem you have. Hot and humid points one way, cool and damp another, and a worn-out gap points to the grass itself. Match what you see below, then act before a patch spreads.
Greasy gray patches that wipe out the lawn in days
This is gray leaf spot, a fungus that hits perennial ryegrass hard in hot, humid weather when the leaves stay wet for hours. Patches run from 4 to 12 inches (10 to 30 cm) across, the blades go matted and gray-fuzzy, and a stand can collapse within a few days. Bag the clippings, water before sunrise so the grass dries fast, and put down a preventive fungicide on a 14 to 21 day cycle through the danger months.
Fix:
- Collect clippings when symptoms appear
- Apply preventive fungicide on a 14-21 day interval during high-risk periods
Bare patches that never grow back on their own
Perennial ryegrass is a bunch grass, so it grows in tight clumps and has no runners to creep across a gap and heal it. Once traffic or harsh weather thins a spot, that spot stays open until you reseed it. Overseed bare areas with fresh seed, or blend in Kentucky bluegrass, which spreads by rhizomes and closes the gaps for you.
Fix:
- Overseed bare areas directly with fresh ryegrass seed
- Blend with Kentucky bluegrass so the bluegrass spreads to fill gaps
Pink patches with red threads on the leaf tips
Red thread shows up in cool, damp spring and fall weather, leaving round patches with a pink cast and tiny red strands clinging to the blade tips. It usually means the lawn is short on nitrogen rather than seriously sick. A balanced feed pushes fresh growth that outpaces the fungus, and mowing off the infected tips while cutting back on evening watering clears it up.
Fix:
- Apply adequate nitrogen to push recovery growth
- Mow to remove infected tips and reduce leaf wetness
Toxicity
Lawn ryegrass is safe. It's a common turf and pasture grass with no toxic parts, so cats, dogs, rabbits, birds, and children are fine around it. The one thing to know is a grazing caveat rather than a poison: pasture stands carrying a fungal endophyte can cause ryegrass staggers in horses and livestock, a forage-management issue, not a danger in the lawn under your feet.
Safe for
People · Cats · Dogs · Horses · Rabbits · Livestock · Birds
Cats None
Perfectly safe. A cat that nibbles a few blades of lawn ryegrass will be fine, and many cats chew grass now and then with no trouble at all.
Dogs None
No concern here. Lawn ryegrass is on the non-toxic list, so a dog can play, roll, and graze on it without any worry.
Horses None
The grass itself is safe to graze. The one caveat is forage management, not poison: pasture stands infected with a fungal endophyte can trigger ryegrass staggers, with muscle tremors and a wobbly, uncoordinated gait when the horse gets excited.
Rabbits None
Fine for rabbits to graze. Fresh lawn ryegrass makes a harmless addition to the greens they already eat.
Livestock None
Safe and widely grown as forage. Watch only for endophyte-infected pasture, where lolitrem B and ergovaline can bring on staggering, incoordination, and heat stress in heavily grazed stands during late summer and fall.
Birds None
No risk. Birds peck the seed and clippings without harm, and the grass holds nothing toxic to them.
People None
A common, harmless lawn and pasture grass with no toxic parts. Children can play on it freely.
Safe as a pet and family lawn; however, turf-type and forage ryegrass can carry a fungal endophyte (Epichloe festucae var. lolii) producing lolitrem B and ergovaline that cause tremors, incoordination, and heat stress in grazing horses and livestock, especially on overgrazed stands in late summer and fall.
Helpline numbers
United States
ASPCA Animal Poison Control: (888) 426-4435 (fee applies)
United Kingdom
Animal PoisonLine: 01202 509000 (fee applies)
Australia
Animal Poisons Helpline: 1300 869 738
Varieties
A few kinds of perennial ryegrass turn up, and the labels are easy to mix up. These are the ones worth telling apart.
Turf-type cultivars
Improved selections with a fine-to-medium texture and glossy dark-green color, bred for dense lawns that stand up to wear.
Winter overseeding ryegrass
Sown over dormant warm-season lawns across the South to keep the turf green right through winter.
Distinct from annual/Italian ryegrass
Annual ryegrass (Lolium multiflorum) is a coarser, short-lived grass, while perennial ryegrass is finer-textured and stays put for years.
Companions
Perennial ryegrass pairs best with a spreading grass that can do the one thing it can't, which is fill its own gaps.
Plant near
Kentucky bluegrass: Spreads by rhizomes to fill the gaps that bunch-type ryegrass cannot self-repair.
How to propagate
Perennial ryegrass grows from seed and almost nothing else, since it makes no runners to root from. The upside is speed: few grasses come up as fast.
SeedEasy
Early fall (or spring) in cool regions; fall for southern winter overseeding. · Germinates in 3-7 days, the fastest of common lawn grasses; uniform turf in about 2 weeks.
Start ryegrass from seed, sown in early fall or spring in cool regions, or in fall for a southern winter overseed. It sprouts in 3 to 7 days, the quickest of the common lawn grasses, and knits into uniform turf in about 2 weeks. Because it grows in clumps with no runners, it never thickens on its own, so reseed to build up thin stands.
Myths
Perennial ryegrass and annual ryegrass are the same plant.
They are two different grasses. Perennial ryegrass (Lolium perenne) is a fine-textured, permanent turfgrass, while annual ryegrass (Lolium multiflorum) is coarser and short-lived, used as a quick temporary cover or a winter overseed. Check the species name on the bag before you buy.