RC Big Rock is a new late season variety of upland switchgrass developed from Cave-in-Rock. Very tall height and high yield potential – likely to reach 7′ tall along the I-35 states, and up to a foot taller moving east to Wisconsin and beyond. It is the tallest upland switchgrass released to date. Genetically improved for ease of establishment, upright growth habit and increased height, making it an ideal choice for high quality habitat for deer and provides a better wintering habitat for pheasants and quail than Cave-in-Rock; better standing than all other commercial upland cultivars of switchgrass.

Large-seeded variety selected for reduced seed dormancy, increased seed weight and increased seedling vigor. Well adapted to drill-seeding. Can be frost seeded. Excellent winter hardiness (Zone 4A) for a late season variety.

Like Cave-in-Rock it grows well on diverse soil types and has a wide regional adaptation to states in the mid-west and northeast regions (Wisconsin, Iowa, Illinois, Indiana, Michigan, Ohio, New York and Pennsylvania). Due its later maturity, it is also well suited for use in Kentucky, Missouri, Nebraska, Virginia and West Virginia.

Best adapted to regions that receive on average greater than 26″ of average annual precipitation. For regions that receive 26-30″ consider a blend of RC Tecumseh and RC Big Rock. For regions that receive more than 30″ use RC Big Rock. For regions that receive less than 26″ use RC Tecumseh.

Summary of Wildlife Benefits

• Provides tall, dense cover for nesting birds, small mammals, and fawns.

• Seeds are a food source for birds like quail, pheasants, and sparrows.

• Improves soil health and reduces erosion, benefiting overall ecosystem stability.

RC Big Rock Switchgrass is a hardy, low-maintenance native grass that enhances wildlife habitat, supports conservation efforts, and is ideal for tall cover and screening.

Key Characteristics of RC Big Rock Switchgrass

• Planting Time:

  • Late spring to early summer (May to June) when soil temperatures reach 60°F or higher.

• Planting Depth:

  • ¼ to ½ inch for optimal germination and establishment.

• Planting Rates:

  • Broadcast: 8-10 lbs of pure live seed (PLS) per acre.

  • Drilling: 5-7 lbs of PLS per acre.

• Days to Maturity:

  • Establishes in 1-2 years, reaching full maturity by the third growing season.

• Height at Maturity:

  • 5-7 feet tall, making it ideal for tall cover and screening.

• Drought Tolerance:

  • High; deep root system allows it to thrive in dry conditions.

• Saturated Soil Tolerance:

  • Moderate; can tolerate occasional flooding but not prolonged waterlogged conditions.

• Shade Tolerance:

  • Low; prefers full sun for optimal growth.

Fertilization Guidelines

• Nitrogen (N):

  • Apply 50-70 lbs per acre at planting, with additional applications of 30-50 lbs per acre in subsequent years if needed for biomass production.

• Phosphorus (P) and Potassium (K):

  • Apply based on soil test recommendations. Typical rates range from 20-40 lbs per acre for P and K.

• pH Range:

  • Prefers a soil pH of 5.5-7.5 for optimal growth.

Herbicide Use

• Switchgrass is slow to establish and may require weed control during the first 1-2 years.

• Pre-Emergent Herbicides:

  • Use atrazine or imazapic (labeled for switchgrass) to control annual grasses and broadleaf weeds during establishment.

• Post-Emergent Herbicides:

  • 2,4-D can be used for broadleaf weed control. Avoid herbicide use once switchgrass is established to protect wildlife habitat.

• Caution: Follow label instructions and avoid herbicides that may harm non-target species.