Rye vs. Ryegrass
Many people, understandably, are confused by the difference between rye and ryegrass. These two plants, despite the similarity in names, are not closely related and do not behave alike.
Rye (Secale cereal) is a cereal grain, closely related to wheat, with which it can be crossed to form triticale. It is tall and coarse with a long head full of large seeds almost as big as wheat. Rye is the most cold-tolerant grain crop known, and will produce more growth during winter than any other crop. It is the last forage crop to freeze down in fall, and the first to green up in spring but is also the first cereal grain to get stemmy and unpalatable in spring. Rye is very tolerant of drought and sandy or low-fertility soil, but responds well to fertility. It does not like very wet soil. One drawback of rye is that volunteer plants are hard to control in wheat fields if allowed to go to seed.
Ryegrasses (Genus Lolium), on the other hand, are true “grassy” plants, closely related to fescue with which it can be crossed to form the hybrid called festulolium. The seeds are small and fluffy, and are very hard to distinguish from fescue seed. The leaves are erect, dark green, and very shiny due to a waxy layer on the leaf surface.
Ryegrasses perform best in clay soils with good moisture, and tolerate wetter soils than any of the cereal grains. They have fine leaves and do not get very tall compared to cereals. Annual ryegrasses form a dense root system that can hold up animals and vehicles much better than cereals in wet weather. Ryegrass greens up later in spring than rye, but is much more grazing tolerant and grows later into the summer than rye. It also keeps its palatability and nutritional value much later in the season than rye. Annual ryegrass is not closely related to wheat like rye and there are herbicides that can take volunteer ryegrass out of wheat. Ryegrass comes in annual, biannual and perennial forms, and even hybrids of annual and perennial varieties (intermediate ryegrass).