Three high-quality grass species for forage in Illinois are timothy, smooth bromegrass, and orchardgrass. A fourth species, tall fescue, is widely grown in Illinois but is lower in nutritive quality than the other three.
Timothy is a cool-season species that goes dormant during hot weather, so it is best suited to the northern half of Illinois. Also, this perennial grass has an onion-like storage structure called a "corm," which enables it to withstand abuses such as overgrazing.
However, timothy is a bunch grass, so it provides less protection from soil erosion than sod-forming grasses such as smooth bromegrass, reed canarygrass, or Kentucky bluegrass. In addition, it is not as high-yielding and offers less midsummer production than smooth bromegrass or reed canarygrass.
Smooth bromegrass and orchardgrass are the other two top grass choices for high-quality feed in Illinois because both are high-yielding, palatable, and adaptable to a wide range of conditions.
Smooth bromegrass is a perennial, sod-forming grass with short rhizomes (underground stems) that establish new daughter plants. The resulting network of roots creates a sod that resists water erosion and makes smooth bromegrass a good pasture grass, especially for sharp-hooved animals such as horses.
Because smooth bromegrass is durable in cold weather, it is well-suited to the northern half of Illinois. It also combines well with alfalfa or red clover and is fairly tolerant of wet soils and short-term flooding. That is why it is often used for grassed waterways in Illinois.
On the other hand, smooth bromegrass has less summer production than orchardgrass or reed canarygrass when moisture is lacking and temperatures are high.
Orchardgrass, a perennial hay and pasture grass, is well-suited to the southern two-thirds of Illinois. Like timothy, it is a bunch grass and thus provides less erosion protection than sod-forming grasses.
Orchardgrass is early maturing, recovers rapidly after grazing, is heat-tolerant and moderately productive during hot summer months if soil moisture and fertility are available. It also combines well with alfalfa.
(For information on other grasses, see these additional descriptions.)