Lawn seed products may be mixtures and blends. Seed mixtures are combinations of two or more species of grass, such as Kentucky bluegrass and perennial ryegrass. Blends of grass seed are combinations of two or more cultivars/varieties of a single lawn species. Cultivars (or varieties) are considered selections of a species. Cultivars may offer a variety of traits that set them apart from others in the species, including resistance to diseases or other stress, or perhaps improved color or hardiness. When combined in blends, each cultivar offers a variety of features to contribute to a diverse stand of lawn grasses able to withstand a number of stresses and problems better than one cultivar by itself.
Combining grass species and cultivars together helps create a uniform yet diverse stand of grasses in a lawn. Mixtures and blends of Kentucky bluegrass, perennial ryegrass, and fine fescues are suggested for lawn use in northern Illinois. The decision of which specific mixture or blend to use is based on site conditions, maintenance program, and use factors. Here are some examples.
Full Sun Areas
Kentucky bluegrass blend (3-5 cultivars)
Kentucky bluegrass blend/perennial ryegrass
Tall fescue blend * (high traffic areas or hot, dry sites)
Fine fescue blend (low maintenance lawn - infrequent mowing)
Kentucky bluegrass/perennial ryegrass/fine fescue
Kentucky bluegrass/fine fescue blend
Tall fescue blend *
**(in order of need for light)
Fine fescue blend (dry shade)
Rough bluegrass (wet shade) - low quality lawn
Full shade tolerant ground cover
Woodland natives (ferns, wildflowers)
Mulch to cover soil
*Tall fescue may not be completely winter hardy in northern Illinois, and may require overseeding on a regular basis to maintain acceptable quality.
**Shade-tolerant grasses have a limit on how much shade they can tolerate.
From Lawn Talk: