They provide a green cover during the winter when the warm-season grasses turn brown after frost. Also, they can be used as a winter cover to help prevent erosion on new lawns where the permanent grass has not been established. However, overseeding may retard the warm-season grass unless managed correctly in the spring, because the ryegrass competes for moisture, sunlight and nutrients. Ryegrass adapts well to either sun or shade. Although cheaper, annual ryegrass is a second choice to perennial ryegrass, since perennial ryegrass has more desirable turf characteristics.
Annual ryegrass dies out in late spring after being planted in the fall.
Perennial ryegrass usually lives somewhat longer than annual ryegrass, especially in the shade. It can survive for years in some areas of the lawn where it can become a nuisance. It has better disease resistance than annual ryegrass. It is not recommended as a permanent lawn, however, because of its susceptibility to diseases in hot weather. Ryegrasses should only be used in South Carolina for overseeding in the fall.