Lolium perenne L.


Perennial, cool-season bunchgrass used commonly as a forage. Closely resembles annual ryegrass but can be distinguished by an abundance of lower leaves and awnless lemmas. Reaches height of 1-2 feet at maturity. Performs well in moist, cool regions with mild winters. Does well in pure stands and in mixtures with legumes or certain other grasses such as orchardgrass and tall fescue.

Soil Protection (Cover Crop)

Species Selection Characteristics

Annual Precipitation (inches): 
20 to 24
24 to 28
28 to 32
32 to 36
36 to 40
40 to 50
50 to 60
60 to 70
70 to 80
80 to 100
100 to 120
120 to 140
140 to 160
> 160
Plant Hardiness Zones (cold tolerance): 
Heat Zone (July Mean Max Temperature): 
< 14 °F
14 to 18 °F
18 to 22 °F
22 to 26 °F
26 to 30 °F
30 to 34 °F
34 to 38 °F
38 to 42 °F
42 to 46 °F
46 to 50 °F
50 to 53 °F
53 to 56 °F
56 to 59 °F
59 to 62 °F
62 to 65 °F
65 to 68 °F
68 to 71 °F
71 to 74 °F
74 to 77 °F
77 to 80 °F
80 to 84 °F
84 to 88 °F
88 to 92 °F
Soil pH Tolerance: 
Strongly acid, 5.1–7.3
Moderately acid, 5.6–7.3
Moderately acid to moderately alkaline, 5.6–8.4
Slightly acid to moderately alkaline, 6.1–8.4
Near neutral, 6.1–7.3
Soil Drainage Tolerance: 
poorly drained
somewhat poorly drained
moderately well drained
well drained
Flooding Tolerance: 
7-30 days
Soil Salinity Tolerance: 
Moderately tolerant, 3–6 dS/m

Identification Characteristics

Growth Season: 

Growth Habit and Stand Life

Habit: Bunchgrass

Life Cycle: 
Short-lived perennial

Climate and Soil Suitability Zones

Climate Tolerances: 

Temperature: 68°F to 77°F. Sharp decline in production after 87°F.

Precipitation: Minimum of 18-25 inches, with 40-60 inches ideal.

Soil Tolerances: 

pH: 5.1-8.4, optimal conditions are 6-7.

Salinity: Moderately tolerant (3-6 dS/M)

Soil Drainage: Well drained to Poorly drained (WD-PD)

Drought Tolerance: Low

Quantitative Tolerances: 

Climate suitability characteristics in the following table are based on field experiments and forage agronomist experience. Soil factor data are based on values provided in Chapter 3 of the NRCS Range and Pasture Handbook (

Climatic and soil factor values for well-suited, moderately-suited, and marginally suited classifications.

  July Max Temp (°C) January Min Temp (°C) Annual Precipitation (mm) Soil pH Soil Drainage Class Soil Salinity (dS/m)
Well-suited 30 -10 600 5.75-7.5 MWD 2
Moderately-suited 32 -15 500 5.5-7.75 SPD-MWD 8
Marginally-suited 34 -20 400 5.25-8.0 WD 8

Response functions were developed from these tabular values using Rstudio scripts, with parameters provided for climatic and soil GIS spatial data layers.

Suitability Maps

Suitability patterns for forage species are caused by different factors in different locations. Low winter temperatures limit the northern range of many species, while low precipitation limits the western range of species in the semi-arid west. Low summer temperatures limit the range of species with increasing elevation while high summer temperatures limit the range in the desert southwest and hot and humid southeast. Soil characteristics (pH, drainage, and salinity) also limit the suitability zones of forage species. However, soil amendments (liming and drainage tiles) can alleviate many of these limitations. Thus, NRCS Soil Survey data should be informed and revised by management mitigations.

Nine maps have been developed; 1) 30-year long-term July maximum temperature 2), 3) 30-year long-term annual precipitation, 4) soil pH, 5) soil drainage, 6) soil salinity, 7) combined climate factors, 8) combined soil factors, and 9) combined climate and soil factors.

Yield Potential and Production Profile

Performs best in moist, cool conditions without harsh winters. Annual yield may reach 2-4 tons dry matter/acre under optimal conditions and proper management. Season of greatest production is mid-May through June.


Perennial ryegrass easily cross pollinates with other species but does not self-pollinate, leading to many varieties developing. Difficulties keeping genetic purity due to propensity for cross pollinating.

Tetraploid varieties stand more upright and are utilized more often as a forage. Diploid varieties are more persistent under grazing and used more often for pasture. 

Management Level Required

Suitable Management Level: 

Quality and Antiquality Factors

Quality Factors: 
  • Very high palatability
  • Quick establishment
  • More persistent than annual ryegrass
  • Recovers rapidly to grazing, tillers extensively
Anti-quality Factors: 
  • Short stand life
  • Vulnerable to drought, high temperatures
  • Susceptible to winterkill
  • Fungal endophyte present in grass associated with neurological disorder in livestock which consume it

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