Research on ornamental grasses has made us cautious. Sources of information vary widely in the hardiness zone numbers. Many are not hardy in Zone 4 where we live. We have tried several that proved not to be hardy. And we feel we want clump-forming grasses rather than those that spread by rhizomes. We don't have many areas that we want a grass to take over.
SPSI Spodiopogon sibericus Frost Grass grows to 3' tall with plumes in fall. Zone 3 gardeners, here's one for you! It is rock hardy!