Cool Season Perennial Grasses Overview

Cool Season Perennial Grasses

• Cool season perennial grasses are the primary pasture and hay species in regions north of Zone A, and many areas in Zone B.
• They are generally more nutritious and have a longer growing season than warm-season perennials.
• Examples include Kentucky bluegrass, orchardgrass, reed canarygrass, and tall fescue.

Kentucky Bluegrass (Poa pratensis)

• Origin: Europe
• Description: Perennial grass with narrow, boat-shaped leaves and an open, pyramid-shaped seed head. Forms a dense sod through rhizomes. Grows 1-3 feet tall.
• Adaptation: Upper parts of Zones C and D. Intolerant of drought and high temperatures.
• Uses: Pasture, limited hay use. High nutritive value.
• Establishment: Seed, 10-15 lb/acre, in August-September or February-March.
• Fertilization: Requires fertilization to be highly productive, often in combination with legumes.
• Seasonal Production: April-October, with limited production in July-August.
• Management: Tolerates frequent, close grazing; best when grazed to 1-2 inches. Clover grown with it increases pasture productivity.
• Pests: Grubs, bluegrass billbug, sod webworms, chinch bugs, frit fly, and greenbug aphid can reduce production.

Orchardgrass (Dactylis glomerata)

• Origin: Europe
• Description: Perennial bunchgrass. Flattened leaf sheaths, tall ligule, blue-green blades, and an open panicle. Grows 2-3 feet tall.
• Adaptation: Upper part of Zone B, Zones C, and D. Less drought- and drainage-tolerant than tall fescue. More shade-tolerant. Does not generally persist more than 2-4 years in the lower South.
• Uses: Pasture, hay. High nutritive value with good management.
• Establishment: Seed, 15-20 lb/acre, in August-September, sometimes in early spring in the upper part of Zone C and D.
• Fertilization: Requires higher fertility than tall fescue, responds well to nitrogen.
• Seasonal Production: March-June or July. Lower production in September-November compared to tall fescue.
• Management: Needs better management than endophyte-infected tall fescue. Avoid close, continuous grazing or frequent close cutting. Harvest first hay in boot to early bloom stage.
• Pests: Armyworms, rust, leafspot diseases, and nematodes (sandy soils).

Reed Canarygrass (Phalaris arundinacea)

• Origin: Europe
• Description: Coarse, sod-forming perennial with wide leaves, rough edges, sharp points, and a panicle seed head. 2-6 feet tall. Deep-rooted, short rhizomes.
• Adaptation: Upper zones C and D. Tolerant of flooding, poor drainage, and drought; soils pH 5-8.
• Uses: Pasture, hay, silage. Some varieties (common reed canarygrass) contain alkaloids, reducing palatability. Lower-alkaloid varieties are more palatable.
• Establishment: Slow establishment due to poor seedling vigor. 5-8 lb/acre, April-May (Zone D) or August-September (Zone C)
• Fertilization: Highly responsive to nitrogen.
• Seasonal Production: April-September; limited July-August.
• Management: Rotational stocking.
• Pests: Tawny blotch, Helminthosporium leafspot, and frit fly.

Ryegrass

• Annual Ryegrass (Lolium multiflorum):

  • Origin: Europe
  • Description: Annual bunchgrass with dark, shiny leaves, soft, clasping auricles, and a spike seed head. Grows 2-3 feet tall.
  • Adaptation: Zones A, B, and some of C. Tolerates wet, poor drainage. Less hardy in winter, higher moisture requirements.
  • Uses: Primarily pasture, but also hay/silage. High nutritive value.
  • Establishment: 10-15 lb/acre (mixes) or 20-30 lb/acre (alone). Plant in September/early October (main season), November overseeding possible in Gulf Coast for warm season grasses.
  • Fertilization: Responsive to nitrogen, tolerant of moderate acidity.
  • Seasonal Production: High production in Gulf Coast high rainfall areas November-May, further north mostly late February - May.
  • Management: Can be planted alone in the Gulf Coast, or with small grains or clover elsewhere. Tolerates close, continuous grazing.
  • Pests: Armyworms; rust disease attack some varieties (especially near Gulf of Mexico)

• Perennial Ryegrass (Lolium perenne):

  • Origin: Europe
  • Description: Perennial bunchgrass with shiny, smooth leaves, short, non-clasping auricles, and a seed head without awns. Larger seeds than annual. Grows 2-3 feet tall.
  • Adaptation: Upper Zone C and D. Well-drained soils with adequate moisture. Less tolerant of drought and heat than tall fescue/orchardgrass.
  • Uses: Pasture, hay, silage. High nutritive value; infected with toxic endophytes can cause staggers syndrome.
  • Establishment: 5-8 lb/acre (mixes), 14-18 lb/acre (alone), spring or late summer.
  • Fertilization: Highly responsive to nitrogen; tolerant of moderate acidity.
  • Seasonal Production: Primary spring/early summer; less autumn production than tall fescue.
  • Management: Rotational stocking preferred; tolerates close grazing; does not stockpile well during autumn/winter.
  • Pests: Usually no serious pest problems.

Small Grains

• Rye, Oats, Wheat, Barley, Triticale:
  • Origin: Iraq, Turkey, Europe
  • Description: Annual bunch grasses, 2-4 feet tall, with various seed head structures.
  • Adaptation: Rye and wheat in Zones A, B, C, D; Oats in A and some B varieties. Rye is more acidic soil tolerant, wheat wets soils, oats cold sensitivity.
  • Uses: Rye-pasture; barley, wheat, oats-pasture, hay, silage; triticale-hay, silage. High nutritive value.
  • Establishment: Usually planted in September/October. 60-90 lb/acre in mixtures, 90-120 lb/acre alone.
  • Fertilization: Highly responsive to nitrogen; requires phosphorus and potassium.
  • Seasonal Production: Zone A-November-April; Zone B-November-December and February-April; Zones C, D - March-June.
  • Management: Adequate stocking rate to use forage and promote new leaf growth. Plant an annual legume (e.g., arrowleaf clover) to extend the productive season. Hay/silage harvest boot to early heading stage.
  • Pests: Rusts, powdery mildew, viruses, Hessian fly, armyworms.

Other cool season grasses

• Smooth Bromegrass

  • Origin: Russia
  • Description: Perennial cool season grass with narrow, smooth blades, erect panicle. Deep-rooted, rhizomatous. Grows 2-3 feet tall. Best on silt-loam and clay-loam soils.
  • Adaptation: Upper C and D.
  • Use: Pasture, hay, silage. Often with legumes (e.g., alfalfa)
  • Establishment: Seed 15-20 lb/acre, August-September or February-April.
  • Seasonal Production: April-October; limited July-August.
  • Management: Moderate rotational stocking best. Avoid continuous close stocking (weakening). Harvest at boot-early bloom stage for hay.
  • Pests: Armyworms, grasshoppers, foliar diseases (humid areas).

• Tall Fescue (Festuca arundinacea):

  • Origin: Europe
  • Description: Perennial bunchgrass with short rhizomes, slightly shiny, dark green leaves with prominent veins and rough edges, compressed panicle. Deep rooted, grows 2-4 ft tall.
  • Adaptation: Zones B, C, D; clay or loam soils; tolerant acidity and poor drainage. Relatively drought tolerant.
  • Uses: Pasture, hay, erosion control; high nutritional value unless containing fungal endophytes.
  • Establishment: Seed drilled 15-20 lb/acre (or broadcast 20-25 lb/acre) in August-September or October and early spring in C & D.
  • Fertilization: Tolerates low fertility and acid soils but responds well to fertilization.
  • Seasonal Production: September-December, March-June/July
  • Management: Endophyte-infected tall fescue can tolerate overuse better; endophyte free/novel variety don't graze closer than 3-4 inches and avoid overgrazing. White/red clover/alfalfa can be used with it. Harvest first hay in late boot stage for best nutrition. Autumn stockpiling is useful.
  • Pests: Fungal endophyte (Neotyphodium coenophialum) strains can drastically affect animal performance. Nematodes are prevalent in sandy soils.

• Timothy (Phleum pratense):

  • Origin: Northern Europe
  • Description: Perennial bunchgrass, bluish-green, narrow, sharp-pointed leaves, large ligule, dense cylindrical spike seedhead, bulb-like corms at the base. 2-4 ft tall.
  • Adaptation: Upper C and D. Cool, humid conditions; poor performance in warmer zones.
  • Use: Primarily hay (popular with horses), also pasture.
  • Establishment: Seed 6-8 lb/acre, August-September or early spring.
  • Fertilization: Requires more fertility than orchardgrass and responds well to fertilization
  • Seasonal Production: April-October; low production August-October.
  • Management: Harvest best nutritive hay in boot to early bloom stage; avoid late-cut hay.
  • Pests: No significant pest problems within its area of adaptation.

Forage Disorders (Animal Health)

• Bloat:
  • Cause: Stable foam in rumen prevents belching (eructation), resulting in gas buildup and potential suffocation.
  • Plants causing bloat: Persian, ball, ladino/white clover, alfalfa, others rarely.
  • Prevention: Avoid turning hungry animals into lush legume/grass pastures; feed dry hay beforehand, avoid wet/frosty pastures. Use surfactants, ionophores, and manage stocking rates.
• Nitrate Poisoning:
  • Cause: High nitrate levels in plants (e.g., stressed corn, fertilized grasses). Reduced moisture/humidity and/or high nitrogen fertilizer usage can increase plant nitrate content
  • Plants causing toxicity: Sudangrass, sorghum-sudan hybrids, pearl millet, corn, wheat, oats, and various weeds.
  • Prevention: Watch animals in suspect pastures/hay; analyze hay (safe up to 2,500 ppm). Do not feed hay over 15,000 ppm.
• Prussic Acid Poisoning:
  • Cause: Glycosides forming prussic acid (HCN) in plants (e.g., Johnsongrass, sorghum, sudangrass). Occurs after frost, drought conditions, etc.
  • Plants causing toxicity: Johnsongrass, sorghum, sudangrass, sorghum-sudan hybrids, wild cherry.
  • Prevention: Avoid grazing just after frost, drought or when green shoots after frost or drought events exist.
• Grass Tetany (Hypomagnesemia):
  • Cause: Low magnesium levels in blood of animals grazing low Mg content plants in late winter/early spring. Especially cows and ewes in early lactation. Soils low in magnesium, or when wet, inhibit plant's ability to absorb magnesium.
  • Prevention: Lime deficient pastures
  • Prevention: Supplemental feeding of magnesium-fortified mineral mix during the tetany season; injections.
• Other Disorders:
  • Acute Bovine Pulmonary Emphysema (ABPE): Results from sudden diet changes (lush pasture). Avoid sudden changes in diet. Feed grass hay if an outbreak occurs.
  • Ergot Poisoning: Parasitic fungus growth in seed heads causing reduced blood flow. Clip pastures, provide ergot-free feed.
  • Bermudagrass Staggers: Nervous disorder: alkaloids from fungal infection. Prevent by maintaining young, healthy pastures; avoid mature or matted bermudagrass.