The perennial ryegrass lifecycle is short with an active growth period during cool seasons, seed production beginning mid-spring and fall, and seed germination in fall and winter. Perennial ryegrass is common for winter overseeding.
Perennial ryegrass is a quick-growth bunch grass with a short lifecycle. It is active during spring and somewhat dormant during dry summer as it cannot withstand restrictive water, drought-like conditions, and high temperatures. Growth recommences in fall as weather cools, and reaches a maximum height of 3.5 feet.
The largest seed bloom occurs mid-spring into summer, and flowering takes place from September to December. Perennial ryegrass seeds are hearty and germinate best during fall, as seeds have more growing time before dormancy occurs. Seeds can germinate in winter and spring; however, freezing or hot temperatures and lack of water damage or kill seedlings. It is best to sow seeds when temperatures are between 50 and 75 degrees Fahrenheit. Seeds easily establish in moderate-to-high soil fertility.
Perennial ryegrass is a permanent lawn grass in northern, western and upper-southern states. Due to perennial ryegrass' ability to tolerate cold and frost, it is desirable for winter overseeding on golf courses, athletic fields and lawns in southern states. It cannot survive below -18 degrees Fahrenheit.