Because ornamental grasses range in height from creeping (as low as 2 inches tall) to towering (some are over 10 feet tall), they can fill every garden nich from groundcover to large "shrub". Use them in the front, middles and back of the perennial border to add sparkle and contrast. Or site tall grass like Japanese silver grass (Miscanthus sinensis) or switchgrass (Panicum virgatum) in the center of an island bed or at the ends of a border to anchor the planting.
Besides providing forms and textures that work well with perennials, ornamental grasses have two very desirable traits that make them valuable in perennial gardens: They catch the light, which seems to shine through the foliage and flower heads, making them glow; and every shimmer in the breeze, moving with every air current. Use these features to add excitement to your garden.
Remember to choose clumping grasses like the fountain grasses (Pennisetum spp.) or feather reed grass (Calamagrostisarundinacea) rather than running grasses when you include ornamental grasses i a perennial garden. As their name implies, clumping grasses form increasingly larger clumps but stay in one place, while running grasses send out creeping stems or roots, which spread like weeds all over the garden (think of crabgrass). If you want to include a running grass like "Feesey's Form' ribbon grass (Phalaris arundinacea "Feesey's Form") because its pink, white, and green variegations are so beautiful, plant it in a deep, sunken bucket with the bottom cut out, or sink a wide metal edging around it to control its spread.
Although most ornamental grasses grow best in a sunny site, there are a number of stunning grasses that grow beautifully in shade. If you want to light up a shady garden, try golden-variegated hakone grass (Hakonechloa macra var. aureola) or one of the many variegated sedges (Carex spp.).
Because the foliage and flowers of ornamental grasses contrast so strongly with most perennials, grasses are excellent complements in the garden Place them where they'' catch the light, and the breeze, to show off their finest qualities. Many grasses have striking foliage colors during the growing season and in autumn.
The boldly striped foliage, upright form, and stately height of zebra grass (Miscanthus sinensis "Zebrinus") make it an excellent accent for a large island bed or perennial border. Zebra grass can grow 7 feet tall and makes a striking specimen plant in a sunny site.
Ornamental grasses are great plants for adding four-season interest to the perennial garden, they produce clumps of vertical or fountain like foliage in spring, bloom in summer, set attractive seed heads and turn color in fall, and hold their form throughout the winter. Many have handsome white, cream, or yellow stripes, which contrast beautifully with the rounded or oval variegated foliage of perennials lke hostas and Bethlehem sage (Pulmonaria saccharata). Others have steel-blue or red foliage.
Some perennials are excellent groundcovers for shade, like sweet woodruff (Galium odoratum), with its whorled leaves and starry white flowers. Imagine this wooded path with just the trees and woodruff; then notice how much lovelier this garden looks when you add ostrich fern (Matteuccia struthiopteris) to provide a contrasting texture and to bridge the height gap between groundcover and trees. Ferns are handsome, low-maintenance perennials, don't forget tham when you design your garden.
Sedges (Carex spp.) - to 2 ft tall; Carex elata has green-edged yellow foliage; Carex morrowii "Goldband" has yellow-edged leaves.
Reed grass (Calamagrostis spp.) - tight 2 to 4 ft clumps; reddish, purple, or cream flowers; Calamagrostis arundinacea "Karl Foerster" has reddish-green flowers in summer that turn gold in fall.
blue fescue (Festuca spp.) - fine-leaved clumps, height varies. Festuca cinerea "elijah Blue" has 8-inch soft-blue leaves; 2-3-foot Festuca mairei has gray-green leaves.
Maiden grass (Miscanthus spp.) - tall, clump-forming; large, plume-like blooms; Miscanthus sinensis "Morning Light" grows 4-5 feet tall, light-green leaf blades edged with white look silvery. Miscanthus sinensis var. strictus grows 4-6 feet; yellow horizontal bands run across the green leaf blades.
Switchgrass (Panicum spp.) - clump-forming, upright, dark-green to gray-green leaves, to 6 feet tqll, airy flowers; Panicum virgatum "Haense Herms" grows to 3.5 feet, reddish fall color; Panicum virgatum "heavy Metal" has blue foliage, yellow in fall, 3.5 feet.
Fountain grass (Pennisetum spp.) - bottle-brush flowers, arching clumps, height varies; Pennisetum alopecuroides "Hameln" has white flowers, dark-green leaves, 12-20 inches tall; Pennisetum alopecuroides "Moudry" reaches 26 inches, black flowers, yellow-orange fall color.