The majority of northern lawns are a combination of Kentucky bluegrass, ryegrass and fescues. Kentucky bluegrass will form the nicest lawn, but it has a very low shade tolerance. Ryegrass can tolerate heavy foot traffic, but does not tolerate extreme cold or drought conditions. Fescues (both tall and fine) are often found in mixes due to their tolerance of shade, foot traffic, cold and drought. When combined correctly, these grasses will form a dense turf that is acceptable for most northern lawns in the U.S.