Like Kentucky bluegrass, perennial ryegrass cultivars vary in their tolerance to diseases. As a whole, perennial ryegrasses have excellent resistance to Summer Patch and should be included in a seed mixture where patch diseases are a problem. Perennial ryegrass is much more vigorous in the seedling stage than Kentucky bluegrass. The fine fescues are excellent low-maintenance grasses in that they do well under low fertility and moisture. They are very fine textured and will produce an attractive turf cover if properly installed and maintained.
Fine fescues are quite tolerant of shade.
Use fine fescues alone or in mixtures with shade-tolerant bluegrasses for shaded lawns. Fine fescues have a few disease problems such as red thread and dollar spot. It does well under low fertility and moisture, and has few disease problems. Tall fescue is much coarser textured than the other cool-season lawn grass species. Tall fescue does not survive harsh winters very well.