Ornamental grasses include not only true grasses (Gramineae) but close relatives such as sedges(Cyperaceae), rushes (Juncaceae), hardy bamboos (particularly the genus Phyllostachys), and others. Here are some ornamental grasses adapted to the Rocky Mountain region:
Xeriscape Grasses for Dry Conditions
Indian grass (Sorghastrum nutans): This grass is native to the North American prairies. The foliage varies in color and has a medium-fine texture. In late summer, tan-yellow seed heads form on stiff stems. The upright seed heads measure 2 to 3 inches wide and 6 to 10 inches long. Flowers are delicate looking and turn bronze as they mature. Cut flowers are good for fresh or dried arrangements. In the fall, foliage first turns yellow then orange. The plant reaches 3 to 5 feet high. The variety 'Holt' blooms early and develops good fall color. The foliage of 'Sioux Blue' is blue; 'Bluebird' is blue-gray. This warm season grass grows best in full sun to light shade. It prefers moderately moist conditions but will withstand drier soils. In its native tallgrass prairie habitat, it receives summer rains and grows in sandy, gravelly and even wet soils. Use indian grass in mass plantings, for naturalizing along highways, and on slopes for erosion control. It also provides a tall accent plant with fall and winter garden interest. Heavy snows can bend the seed stalks.
Little bluestem (Schizachyrium scoparium, Andropogon scoparius): The outstanding features of this Great Plains grass are the fluffy, white seed plumes that rise well above the foliage, and the orange to russet-red fall color that often lasts well into winter. The foliage is medium textured and ranges from green to blue-green to blue. Clumps grow 2 to 3 feet tall. Little bluestem is a warm season grass that requires drier conditions and is drought tolerant. Grow in full sun on a variety of soils except wet or mucky ones. This grass is useful when massed in transition areas, for erosion control, and as single specimens in borders. It is a good source for cut flowers. Named varieties are worth looking for but may be hard to locate. 'Cimmaron' has excellent blue foliage. Grow 'Blaze' for its intense fall color that varies from pink-orange to red-purple.
Prairie dropseed (Sporobolus heterolepis): This North American native grass grows 3 feet high. Its thin, fine textured leaves are emerald green and grow in upright, arching hummocks. Leaves turn gold to orange-red in fall. The sweet-smelling, late-summer blooms are tannish brown and cloudlike.
Prairie dropseed is drought and heat resistant but benefits from some summer water. Grow it in full sun in many soil types, including rocky ones. This somewhat warm season accent plant for hot, dry locations adds fragrance to the garden. The seeds attract birds and other wildlife. It is also useful as a tall groundcover.
Grasses for Moderately Moist to Moist Gardens
Feather reed grass (Calamagrostis acutiflora 'Stricta': The wheat-like look of this grass makes it one of the showiest and most popular grasses. The foliage is medium green, stiff and 1/2 inch wide. It grows in an upright, arching clump that reaches 2 to 3 feet tall. Leaves turn orange to yellow in the fall. The straight, greenish flower spikes form in May to June, turn golden, then bleach buff and persist into the winter. This is a partially cool-season grass for full sun. It tolerates heavy soils and grows in medium-dry to moist conditions. Grow it as a single specimen plant for a vertical accent. It also can be grouped for a horizontal swath of golden flowers. Feather reed grass makes a good background plant where a handsome, stately look is desired. 'Overdam' is a variety with white variegated foliage and requires partial shade. In colder areas with a shorter growing season, Foerster's feather reed grass blooms earlier (Calamagrostis arundinacea 'Karl Foerster').
Japanese blood grass (Imperata cylindrica 'Red Baron' or var. rubra): This grass is noted for its red and green foliage and no blooms. It grows upright between 1/2 and 1 foot tall and forms spreading colonies. Use barriers or pots to contain it. Avoid heavy soil. Fall color is deep red to maroon. Its eye-catching appearance can be overused if not matched with appropriate landscape plants. This warm-season grass requires moderately moist to moist conditions and winter water. It prefers midday shade; its appearance suffers in bright sun and heat.
Moor grass (Molina caerulea): This upright, arching plant with stiff flower stems reaches 7 feet tall. The foliage is 1/2 inch wide and light green with a yellow fall color. Flowers are brown, yellow or purple and fade to a tawny buff. Both flowers and leaves break off at the base, minimizing winter interest.Moor grass is a warm-season grass that does best in moist soil and full sun but tolerates light shade. It does poorly in very alkaline soils. Use moor grass as an accent plant in borders either singly or in masses. It makes good fresh or dried flowers. 'Heidebraut' is a compact variety that grows 4 feet tall. 'Moorhexe' is the same height with purplish flowers. 'Skyracer' grows tall, robust foliage and 'Windspiel' has tall, golden flowers.
For more information, please see fact sheet 7.232, Ornamental grasses.
