Ornamental grasses may be annuals or perennials; short or tall; spring or fall flowering; prolific self-seeders or sterile; invasive spreaders or well-behaved clump-formers. They add two elements to the the garden that are not provided by many other plants: movement and sound.
Most grasses will grow in areas where other plants will not survive. There is no “maintenance-free” plant but ornamental grasses are truly low-maintenance. They grow in almost any garden soil, seldom needing watering once established and are rarely bothered by pests or diseases.
Types of Ornamental Grasses
Running grasses are also called spreading or creeping grasses. They spread by means of above ground stems called stolons or underground stems called rhizomes. Many running grasses can be invasive.
Clumping grasses, which grow in tufts, are often called bunch grasses. These grasses vary in size, from little 2-inch mounds of bearskin fescue to much larger plants like pampas grass.
There are four basic categories used to define the shapes of grasses:
Tufted: Usually spiky foliage or fine-textured with upright leaves arising from a base clump.
Mounded: Somewhat weeping, mounded foliage. Top growth covers lowers leaves.
Upright: Foliage grows vertically in uniform or even columnar
Arching: Foliage arches up and out in somewhat equal proportion.
Light and Soil
Most ornamental grasses prefer full sun. Some can tolerate a bit of shade but it’s always best to check before planting. In general they prefer well-drained soil that has been enriched with compost or other organic matter. Ornamental grasses are available that will thrive in a wide range of soil pH.
Planting and Mulching
Ornamental grasses can be planted at any time of year. They should be planted no deeper than they were at their previous growing depth and should be well-watered after transplanting. Maintaining uniform soil moisture around the plant hastens its establishment. Grasses planted too deeply can develop root diseases or simply rot in the ground.
Planting in the spring to early summer is best to allow root systems to establish. If planting in the fall, be sure to provide a light cover of straw or hay during the following winter for best results. Apply mulch after several hard frosts. Any kind of mulch will do, but bark is particularly good. Make sure not to bury the crown. Mulching will also aid in weed control.
Grasses should be well-watered the first season after planting to develop a root system. Established plants do not need regular watering but may need supplemental watering during dry periods.
Ornamental grasses require relatively low levels of fertilization. An application of a slow-release 8-8-8 fertilizer such as Plant-O-Ganic in the spring is enough to suit the plant’s needs throughout the summer. Fertilizer should be watered in thoroughly.
Division depends on the spacing and appearance of the plants as well as the overall health. Plants suffering from die-out in the center should be divided to improve appearance. Division can be done in the spring before growth resumes or in late summer or fall after the growing season.
Diseases and Pests
Ornamental grasses are disease and pest resistant. You may spot some aphids but they can easily be rinsed off with a garden hose. These grasses are quite deer resistant also, as deer find their sharp-edged leaves unpalatable.