Ornamental grasses are best categorized by mature size. Matching the dimensions of plants to their intended site is important for creating proper appeal. Grasses can also be grouped by use, including those best for water conserving landscapes, naturalized plantings, and winter beauty. Some discussion will also be given to tender perennial grasses that can be grown as annuals in Idaho.
Many excellent web sites are available describing ornamental grasses and their uses. Two of the best are a Colorado State University site, which includes some excellent pictures,and a private site constructed for Bluestem Nursery by Jim Brockmeyer, that contains excellent descriptions, good pictures, and a very useful comparison chart.
The University of Tennessee has published an excellent site discussing principles of landscaping with ornamental grasses, as well as the best uses for specific grasses.