Perennial ryegrass (Lolium perenne) is a weed that has many uses but is unlikely to get the recognition it should. Kentucky bluegrass is known as the ideal turfgrass, fescue is known for shade and low maintenance, and perennial ryegrass is typically known for quick germination and little more. Not that quick germination isn’t a good trait they’re known for, but German ryegrass is much more than a nurse’s grass.
It germinates very quickly and can turn from scattered seed to mowable lawn in about 21 days. Perennial ryegrass is considered nurse grass because it is often included in grass seed mixes, largely because of its ability to germinate quickly and provide shade and shelter to other grasses such as Kentucky bluegrass, which can take up to three weeks to start.
Perennial ryegrass is an impressive turf grass in and of itself. It’s a tough, easy-care grass that has built in elements of insect and disease resistance. It is a pleasant pale green color and happens to be the main type of turf at the August National Golf Club (home of the Masters) and the Wimbledon tennis club. It is great for reclaiming construction land and can quickly prevent erosion when used on steep banks such as roads and ditches.
The main problem that perennial ryegrass has, on the other hand, is how it grows. It forms clumps and cannot spread through runners or rhizomes like other types of grass. As a result, it can sometimes appear blotchy and bald spots need to be re-sown regularly as they won’t fill up on their own.Perennial ryegrass can also have difficulty thriving in shady locations that prefer open, sunny locations.
It’s known to be coarse in texture and dull mowers have a tendency to shred rather than shear the leaf blade, but newer improved varieties have largely eliminated the problem. Perennial ryegrass performs better in the transition zone and the less extreme areas of the north. The harsh winters in the upper northern states and Canada can kill perennial ryegrass.
Perennial ryegrass is great for seed mixes, especially to round off the many qualities of Kentucky bluegrass and fescue. With a few well-chosen varieties of all three grasses, a well-thought-out seed mix will thrive in a lawn and all of the different microclimates that can be within a garden. It makes most sense to use a seed mix rather than relying on a specific type of grass, especially if there are shade trees alongside sunny areas and other extreme differences in the garden.
German ryegrass is also popular as winter grass in southern climates. In areas where warm season species dormant in winter, ryegrass is often dotted to provide color for the winter season. When the heat of summer returns, so does the warm season lawn.
Things to consider
It is important not to confuse perennial ryegrass (which returns year after year) with annual ryegrass. Lolium multiflorum, (which dies out after one season). Annual ryegrass is sometimes used as a wintergreen, but it’s also used in cheap, low-quality seed mixes because it is cheaper than high-quality perennial ryegrass seeds. It can be useful in a pinch, or where it may not be wanted the following season, or even because it coexists better with centipede grass than perennial rye, but it is also used to fool ignorant customers.