This is not consistent with most authors, who do not recognize a need for stratification. This type of transient seedbanking is related to exploitation of grasslands that are subject to seasonally predictable drought damage, such as those of Mediterannean climates. Along roadsides and in disturbed habitats in the United Kingdom, perennial ryegrass will reproduce well from seed. The success of self-seeding for stand maintenance in the United States would appear to depend on the ability of seedlings to establish well before frost. It does not thrive where there are extended periods of low temperatures or drought.
Perennial ryegrass begins growth early in spring.
Maritime populations of perennial ryegrass are intermediate. The differences appear to be dependent on temperature, perhaps due to past climatic selection. Populations in Mediterranean climates are adapted to mild, moist winters and can grow year-round, but populations in continental climates are winter dormant. The peak stem carbohydrate reserve levels occur in early summer, just after flowering begins, dropping off through summer to a low in October. This is in contrast to many other grasses that have two peaks of carbohydrate reserves, one in early spring which is depleted by flowering, then replenished by late summer.