Ryegrass grows best in mild climates without extreme hot or cold temperature ranges. In hot climates, ryegrass is more tolerant of shade since the shade reduces the temperature. Part shade or dappled shade will improve lawn health over full shade. In the northwest and northeast, it can tolerate part shade but should receive several hours of sunlight per day. Extreme cold temperatures such as those found in the Midwest will most often kill ryegrass.
Perennial ryegrass is commonly mixed into lawn seeding mixtures because it germinates and establishes quickly, which helps to prevent erosion and adds green to an area immediately. In shaded areas, ryegrass will germinate normally and grow to cover the area for the first year, but it soon tends to thin out, becoming sparse and sometimes diseased. It is often mixed with a shade-tolerant grass so that the ryegrass can quickly establish and prevent erosion while the shade grass fills in more slowly.
Since ryegrass is one of the best cool season grasses, it is sometimes over-seeded in southern climates for fresh grass growth during the winter months when bermudagrass and other heat-resistant grasses are dormant. Since ryegrass grown in shade tends to become sparse, this over-seeding could be done with either perennial ryegrass or Italian annual ryegrass to a similar effect. Italian annual ryegrass would grow through the cool season and die off rather than reseed itself if mowing is regular.
Both perennial ryegrass and Italian ryegrass are tolerant of heavy foot traffic and are the most resistant to wear of all the cool season grasses. In addition, ryegrass is more tolerant of wet or soggy conditions than many grasses, making it a good choice for areas that transform into muddy paths each winter. For these same reasons, perennial ryegrass is often used around homes, at schools, in parks and sporting fields. In landscapes, it may be planted in dappled light through deciduous trees or in areas that receive partial sun each day.