Some grasses and grassy plants have lovely blue foliage and can be planted in a mass to create an oasis of color. Blue grassy plants have a calming influence among other plants that have brighter foliage or flowers, such as yellow, orange or gold. They are good accent plants for white, pink and purple flowers, as well as for gray or green foliage.
There are warm- and cool-season blue grasses, in addition to blue sedges and rushes that can be used in the home landscape.
Sedges (Carex spp.) and rushes (Juncus spp.) are two species of plants that are referred to as "grasslike" and are used like grasses.
Carex glauca grows in a 6-inch-tall clump and has grayish blue foliage. Carex Bunny Blue (C. laxiculmus 'Hobbs') has 8- to 12-inch-tall silvery blue foliage that droops. Carex 'Blue Zinger' grows in a 10- to 20-inch-tall clump with blue-gray leaves.
Juncus 'Blue Arrows' has upright grayish blue foliage that grows 10 inches tall and 'Lovesick Blues' has steely blue foliage that grows 2 to 3 ½ feet tall. 'Blue Medusa' has 12- to 18-inch blue-gray spiral foliage.
Cool-season grasses grow from early winter to late spring and go dormant during the summer. They usually bloom in the summer before dormancy.
Blue Lyme Grass (Lymus arenarius) is a spreading type of grass that grows 2 to 3 feet tall and is used to stabilize slopes and dunes. Blue Oat Grass (Helictotrichon sempervirens) grows in 2- to 2 ½-feet-tall tufted clumps.
Several varieties of fescue (Festuca spp.) grasses are blue. They grow in small clumps and range in size from 6 to 18 inches tall. 'Siskiyou Blue' is spruce blue, 'Elijah Blue' is powder blue and 'Boulder Blue' is very blue.
Warm-season grasses grow in the spring and summer, bloom in the fall and go dormant in the winter. The blooms usually persist throughout the winter.
Varieties of Switchgrass (Panicum spp.) grow in upright clumps. 'Dewey' has 3- to 4-feet-tall powder blue leaves, 'Heavy Metal' has 4- to 5-feet-tall grayish blue foliage, and 'Dallas' has 6- to 8-feet-tall intense blue leaves.
Sorghastrum grasses grow in 3- to 6-feet upright clumps. 'Bluebird' is bluish gray, 'Indian Steel' is blue-green, and 'Sioux Blue' is bright blue.