Perennial Ryegrass (Perenne)

The Perennial Ryegrass (Perenne) is generally described as an annual graminoid. This is not native to the U.S. (United States) and has its most active growth period in the spring and fall . The greatest bloom is usually observed in the mid spring, with fruit and seed production starting in the spring and continuing until summer. Leaves are not retained year to year. The Perennial Ryegrass (Perenne) has a short life span relative to most other plant species and a rapid growth rate. At maturity, the typical Perennial Ryegrass (Perenne) will reach up to 3.5 feet high, with a maximum height at 20 years of 0 inches.

The Perennial Ryegrass (Perenne) is easily found in nurseries, garden stores and other plant dealers and distributors. It can be propagated by seed. It has a moderate ability to spread through seed production and the seedlings have high vigor. Note that cold stratification is not required for seed germination and the plant cannot survive exposure to temperatures below -18°F. has low tolerance to drought and restricted water conditions.

Uses of : Landscaping, Medicinal, Culinary, etc.

Perennial ryegrass is a valuable forage and soil stabilization plant. This species is the predominant forage grass in Europe, and has been used in the United States for forage and lawns. Generally speaking, the tetraploid cultivars are used for forage, and diploid cultivars are for lawns and conservation plantings. Users should double check the intended use of the available cultivars before buying seed. Italian ryegrass is primarily used for quick cover in erosion control plantings.

General Characteristics

Perennial ryegrass grows from 1 to 2 feet tall with a bunchy form, and has medium longevity. Some turf varieties are longer lived. There are numerous long, narrow, stiff leaves near the base of the plant. The under surfaces of leaves are bright, glossy, and smooth. Inflorescence stems are nearly naked. Seedheads are spikes with spikelets growing edgewise to the seedhead stem. Seeds do not have awns (bristles). There are approximately 230,000 seeds per pound.

Italian ryegrass is quite similar to perennial ryegrass except it is an annual or biennial, depending on climate and/or length of growing season. It may grow a little taller than perennial ryegrass: from 2 to 3 feet tall. The seeds of this sub-species have awns.

Required Growing Conditions

These grasses have a wide range of adaptability to soils, but thrive best on dark rich soils in regions having mild climates. They do not withstand hot, dry weather or severe winters. They will stand fairly wet soils with reasonably good surface drainage.

Perennial ryegrass is distributed throughout the entire United States.

Cultivation and Care

A fine, firm seedbed gives the best results. Mulched seedings on graded soil germinate readily. Spring seedings of ryegrass may occur in March, April, or May. Perennial ryegrass may also be seeded mid-August to early September. Seeding rates will vary with local conditions and purpose of plantings. Generally, a rate of 20 to 25 pounds per acre is used if ryegrass is seeded alone. Lesser amounts per acre are used in mixtures, depending upon uses and companion species. Do not exceed 4 pounds per acre in mixes with alfalfa.

General Upkeep and Control

Ryegrass is generally cut for hay when seed is in the soft-dough stage. Ryegrass responds well to good management, such as intensive rotational grazing and fertilizer applications.

Pests and Potential Problems This section is under development.

Cultivars, Improved, and Selected Materials (and area of origin) Ryegrasses cross-pollinate freely so many types have developed. It is difficult to maintain their genetic purity; consequently, Italian ryegrass is marketed as common ryegrass or domestic ryegrass, and it is often a mixture of annual and perennial species. There is no certification of this seed since pure varieties of Italian ryegrass are almost non-existent.

There are many cultivars of perennial ryegrass available for turf application. Newer turf-type cultivars are often intentionally infected with an endophytic fungus to improve stress-tolerance. Tetraploid forage cultivars also abound.

Seed of cultivars and common annual ryegrass is readily available from local commercial suppliers.

Plant Basics
Growth Rate Rapid
General Type Graminoid
Growth Period Spring, Fall
Growth Duration Perennial, Annual
Lifespan Short
Plant Nativity Introduced to U.S.
Commercial Availability Routinely Available
Physical Characteristics
Bloom Period Mid Spring
Displays Fall Colors No
Shape/Growth Form Bunch
Drought Tolerance Low
Shade Tolerance Intolerant
Height When Mature 3.5
Vegetative Spread None
Flower Color Yellow
Flower Conspicuousness No
Fruit/Seed Abundance High
Fruit/Seed Seasonality Spring Summer
Seed Spread Rate Moderate
Gardening Characteristics
Propagations (Ways to Grow) Seed
Moisture Requirements High
Cold Stratification Required No
Minimum Temperature -18
Soil Depth for Roots 10
Toxic to Nearby Plants No
Toxic to Livestock No
After-Harvest Regrowth Rate Moderate
After-Harvest Resprout Ability No
Responds to Coppicing No
Growth Requirements
pH Range 5–8 pH
Precipitation Range 30–30 inches/yr
Planting Density 0–0 indiv./acre
Soil Textures Fine, Medium
Soil Depth for Roots 10
Minimum Frost-Free Days 100 day(s)
Salinity Tolerance Medium
CaCO3 Tolerance Medium
Sustainability & Use
Leaf Retention No
Palatability Low
Fire Resistant No
Causes Livestock Bloating None

Source: USDA, NRCS, PLANTS Database,
National Plant Data Center, Baton Rouge, LA 70874-4490 USA