Ornamental Grasses

Pennisetum alopecuroides- fountain grass, ornamental grass

Long relegated only to the lawn, ornamental grasses are increasingly being used to provide interesting texture and form in the garden. Their adaptability and beauty make them perfect companions to flowering plants, trees, and shrubs. Once established, ornamental grasses require very little care. They add distinction and drama to your summer and winter landscape.

Many grasses make beautiful, low-maintenance garden plants. The grass, or Gramineae, family includes lawn grasses, bamboo, cereals such as wheat and rice, and ornamentals such as fescue and fountain grass. Some of the plants used as ornamental grasses are not grasses at all. Rushes and sedges are grass-like plants that can also be valuable additions to a landscape.

Choosing Grasses

Ornamental grasses are available in a variety of colors, shapes, textures and sizes. In the garden, use them as fillers or specimens, border or background plants, as ground covers or screens. Many look great in container gardens.

Just looking at a little grass plant at the nursery, it's hard to appreciate what it will look like in the garden. View ornamental grasses in a garden setting to get a good idea of the beauty and usefulness of each species. Plants may grow in low mounds, tall clumps, or densely spreading mats. Foliage colors include various shades of green, blue, and red. Variegated varieties may have red, white or yellow bands or stripes. In the fall, foliage often becomes even more beautiful, changing color to hues of red and brown.

The flowers and seed heads are equally diverse, ranging from barely noticeable to truly spectacular. Many are excellent for drying. Allow flowers and seed heads to remain on the plants, and they will provide interest long into the winter.

Here are some of the most commonly grown ornamental grasses:

  • Chinese Silver Grass, Miscanthus sinensis, is grown for its large size, dense growth habit, and unique, fuzzy, silver flowers. Some species may be invasive in certain situations.
    Chinese Silver Grass, Miscanthus sinensis
  • Blue Fescue, Festuca glauca, is known for its attractive blue foliage and compact mounds.
    Blue Fescue, Festuca glauca
  • Feather Reed Grass, Calamagrostis acutiflora 'Karl Foerster', grows to be a large, upright clump, 4 to 5 feet high by 2 to 3 feet wide.
    Feather Reed Grass, Calamagrostis acutiflora 'Karl Foerster'
  • Fountain Grass, Pennisetum, forms mounds of dense, bottlebrush-like flowers. It is hardy in zones 5 through 9 and is often grown as an annual in colder climates or in containers.
    Fountain Grass, Pennisetum
  • Japanese Forest Grass, Hakonechloa macra 'Aureola', grows 12 to 16 inches tall and spreads about 2 feet. The slender stems support gracefully arching leaves. Plants expand slowly by rhizome.
    Japanese Forest Grass, Hakonechloa macra 'Aureola'
  • Pampas Grass, Cortaderia selloana, is a showstopper with tall, erect, silver-white to pink plumes. Proper placement is crucial; plants may be invasive in certain situations.
    Pampas Grass, Cortaderia selloana
  • Sedge, Carex, grows 4 to 24 inches high by 6 to 18 inches wide, depending on the species. Most sedges prefer moist soil and grow in zones 4 through 7. Many have bright, sometimes variegated, foliage.
    Sedge, Carex
  • Switch Grass, Panicum, is an upright plant known for its finely textured flowers and bright red fall color. 'Heavy Metal' and 'Prairie Sky' are popular cultivars.
    Switch Grass, Panicum
  • Tufted Hair Grass, Deschampsia, produces finely textured, 2- to 3-foot mounds in sun or part shade. It grows in zones 4-9 and tolerates moist or dry soil.
    Tufted Hair Grass, Deschampsia

Planting

Plant ornamental grasses in spring through fall. Properly prepare the planting area with plenty of organic matter such as compost.

Spacing

When planting grasses, pay close attention to spacing. If spaced too closely, the effect of the individual plants can be lost. Tall grasses should be spaced about 4 to 5 feet apart; smaller species, 1 to 2 ½ feet. Requirements vary by species.

Care & Maintenance of Ornamental Grasses

Ornamental grasses require little maintenance. They rarely need deadheading or staking and are almost never attacked by pests or disease. But you do need to know how to water and feed them, how and when to divide them, and when to cut them back.

Water

Be sure to keep plants well watered the first season, while they are getting established. Established plants do not need regular watering, but may need some watering during droughts. The amount of water needed depends on the grass species, the site, and on the quality, size and growth rate desired.

Fertilizer

Ornamental grasses don't require much fertilizer. Too much nitrogen can cause plants to grow tall and floppy. Feed grasses with a slow-release organic fertilizer or compost in spring.

Mulch

A heavy application of mulch will greatly reduce the need for weeding and watering. If necessary, cultivate around plants to control weeds.

Winter Protection and Spring Clean Up

Grasses do not need to be cut down before winter. The foliage remains attractive and helps insulate the crown of the plant over the winter. In cold areas, it's a good idea to cover grasses with leaves or straw over the first winter. In spring, cut back the dried foliage to about 4-6 inches.

Division

Ornamental grasses can be divided in the spring or late summer. Dig up the entire clump and separate sections with a sharp spade. You may wish to divide clumps that have grown too big or too close to other plants. If a grass plant dies out in the center, it should be divided. Dig out the clump, divide it, discard the core, and replant part of the division.

Uses

  • Include grasses in perennial borders to take advantage of their interesting foliage and long bloom periods.
  • Use them as temporary, summertime screens around patios.
  • Use them as accents in container gardens. Purple Fountain Grass and Japanese Forest Grass looks especially nice mixed with flowers and other foliage in pots.
  • Use ornamental grasses in place of shrubs. Dramatic perennial grasses can help round out the selection of trees and shrubs in your yard. Once mature, grasses can be about the size of a shrub, but they don't require any pruning.
Ornamental Grasses