We are all familiar with low-growing, running grasses like the St. Augustine and centipede used to cover lawn areas, and, in most gardeners’ minds, all other grasses are simply weeds.
Ornamental grasses, however, are an often overlooked group of herbaceous perennials that thrive in the Louisiana climate and will grow beautifully with minimal effort.
The term “ornamental grass” is applied to grasses and grass-like plants that are used for their beauty. They are a large and complex group of plants with a wide range of growth habits and cultures.
In a strict sense, true grasses are members of the Poaceae or grass family. Many other plants that we think of as grasses are actually sedges and rushes – which belong to different families altogether. But those, along with the true grasses, comprise the bulk of plants we call ornamental grasses.
Many gardeners consider the term "ornamental grass" a contradiction in terms. To be honest, some of our worst garden weeds are grasses. Crabgrass, torpedograss, wild bermudagrass, nutsedge and Johnsongrass are persistent, difficult-to-control pests that many of us are all too familiar with. As a result, many gardeners are reluctant to purposefully plant grasses into flower beds or borders in their landscape.
Ornamental grasses, however, are truly attractive and not rampantly aggressive. But like their weedy cousins, they are tough, resilient and susceptible to virtually no insect or disease problems. Ornamental grasses are an excellent choice for gardeners trying to create a landscape that is more self-reliant – requiring less spraying, fertilization and maintenance.
The strong vertical or fountaining form of many ornamental grasses, combined with their feathery flower heads, makes a unique contribution to the landscape. The leaf blades add fine texture and colors, such as metallic blues, burgundy, white, creamy yellow and every shade of green imaginable.
As grasses grow and seasons change, so does their appearance. The foliage may change color from spring to summer to fall.
Grass foliage also moves in breezes and catches the light like few other plants. And they offer an impressive array of flower plumes and seed heads for interest at various times throughout the year.
Most ornamental grasses grow best in full to part sun, but they are tolerant of a wide range of growing conditions.
If you are planting ornamental grasses into an existing bed, little improvement will be needed. Turn the soil and then incorporate a 2-inch layer of organic matter in the area to be planted. Then be careful to plant the ornamental grass at the same level it was growing in the container and water it well. Water them thoroughly once or twice a week until they are established. Then just sit back and relax.
Some ornamental grasses are evergreen, but most go dormant for the winter. At some point before the end of February, based on our Louisiana growing season, cut the plants back to within a few inches of the ground. When you cut them back during the winter depends on whether you like the appearance of the dead foliage or not. Cutting back must, however, be done before the fresh, new growth comes up in spring
You’ll enjoy creating interesting combinations of ornamental grasses with other plants in your landscape. They are easy to use in beds and borders, enriching neighboring plants with their presence.
Try maiden grass (Miscanthus sinensis) cultivars with bold-leafed tropicals like gingers, cannas or crinums. Pink pentas and blue daze are just one possible combination with purple fountain grass (Pennisetum setaceum ‘Rubrum’). The genus Muhlenbergia (muhly grasses) includes many attractive species excellent for landscape planting.
These rugged plants also can function as important structural features of the landscape. Tall grasses, such as pampas grass (Cortaderia selloana), vetiver (Vetiveria zizanioides), sugarcane (Saccharum officinarum) and giant reed (Arundo donax), can be used to divide the landscape into distinct spaces and are effective as hedges or screens.
An excellent reference on the subject is Ornamental Grasses for the Southeast by Peter Loewer from Cool Springs Press. This book contains an easy-to-use, A-to-Z format featuring most of the annual and perennial ornamental grass species available in the United States. It’s illustrated with color photographs and contains chapters on bamboos, reeds and sedges and other plants that look like grasses.
Ornamental grasses are becoming increasingly available at local nurseries and garden centers. It’s time to get beyond lawn grasses and take a look at this other category of grassy plants. You’ll really appreciate what they can add to your landscape.