Southern States® Annual RyegrassSouthern States Annual Ryegrass is a bunchgrass with shiny, dark green blades that grow 2 to 3 feet tall. It's a highly nutritious pasture grass seed for foraging livestock, and also perfect for hay or silage. Ryegrass is also used widely for erosion control. September or early October are generally the best months to plant Southern States Ryegrass seed to ensure lush pastures come spring.