Ryegrasses are annuals or perennials with hairless, flat leaf blades. Spikelets are widely spaced and alternate on the flowering spike. Perennial ryegrass is a permanent lawn choice in cooler climate areas, and annual ryegrass is seeded yearly and lives for one season. Both perennial and annual ryegrass can provide a green winter lawn when overseeded on warm-season grasses that go dormant in the fall or winter. Used on newly sown lawns of cool- and warm-season grasses, it acts as an erosion barrier while the permanent lawn develops and gives any area a green coverage. Turf managers often overseed bermudagrass with perennial ryegrass to provide a dense green turf during winter months. Depending on the climate, overseeded perennial ryegrass persists anywhere from 3 to 9 months. Although overseeding provides benefits, the spring transition from perennial ryegrass to bermudagrass can be troublesome and inconsistent due to heat-tolerant perennial ryegrass varieties and variable weather conditions in spring and early summer. Perennial ryegrass may survive longer into spring than is desired due to cool and wet conditions, and delay the transition of bermudagrass out of dormancy. High temperatures can result in perennial ryegrass transitioning out before bermudagrass can fill in. This may lead to poor playability and poor usability of the turf.
