Institute of Food and Agricultural Sciences
Hendry County Horticulture News
Ornamental Grasses - Low Maintenance with a Flair
Although grasses are an important component of our native flora, local gardeners have only recently started incorporating them into landscape plantings. In addition to their natural beauty, ornamental grasses are appealing because they tolerate drought, wetness, and fluctuating temperatures. They are resistant to most diseases and insect pests and require minimum inputs of fertilizer. These characteristics are useful to gardeners interested in a low input or sustainable landscape.
True grasses belong to a specific plant family - Graminaceae. However, from a landscape point of view most grass like plants, such as sedges and rushes, are included as ornamental grasses and serve the same function in the landscape.
Ornamental grasses vary in size, shape, color and texture in both foliage and inflorescence (seed head). Mature plants may range in height from 6 inches (white bracted sedge) to 12 or more feet (pampas grass). Grass forms vary from low mounding to fountain shaped to tall vertical. Foliage color includes shades of green, yellow, blue, red, brown and variegated (green and white mixed). A number of grasses change in foliage color in the fall to displays of straw yellow, orange, red or purple. Foliage texture varies from fine to coarse. The inflorescence also varies in size and color, and may change color in the fall as well.
Ornamental grasses can serve many functions in the landscape. Ornamental grasses aren't a static landscape element. Instead, they add life, motion and sound to plantings. Grass foliage provides a surface to catch the wind. This movement adds a sense of motion to the landscape. For this reason the prairies were often visually described as an inland sea. The movement creates a rustling sound adding another dimension to your design.
In a border, grasses can be either edging or background
plants while larger specimens can be accent plants or screens. Rhizome
or stolon forming grasses will stabilize banks or serve as ground cover.
Some diminutive species can be utilized in a rock garden. Combine grasses
with either woody or herbaceous perennial plants, such as fire bush or
black-eyed Susan, to create a low input or sustainable landscape.
Although a few can tolerate shade, most grasses require full sun. Some grasses or grass like plants are adapted to wet soils, but most require a well drained soil.
Before you plant in a new site, test the soil. The soil test will determine the soil's phosphorous and potassium levels, and the pH. content. Adjust these as needed before planting. If your soil needs phosphorous, potassium, or lime, incorporate them thoroughly before planting. Incorporating organic matter into the root zone will improve water holding capacity and oxygen levels. The improved root zone area will allow for maximum root expansion and water extraction from the soil. Improving the soil will reduce irrigation frequency.
Use foliar appearance as a guide to nitrogen requirements. To prevent lodging, flopping or the need for staking, keep soil nitrogen levels low. If leaves are not a normal green color, nitrogen or a micro nutrient may be needed. Unsatisfactory foliar color could also indicate low soil oxygen levels, inadequate drainage or excess watering.
Until a mature root system is developed, newly planted grasses will require irrigation. To reduce the likelihood of foliar disease, consider drip irrigation on specimen plants. Be careful not to over water drought tolerant grasses. Once grasses mature, frequency and quantity of water required varies with grass species and environment.
Broad-leaved weeds are more readily controlled than grass or grasslike weeds. Because selective herbicides are not available for grassy weeds among ornamental grass plantings, you must eliminate weedy grasses before the site is planted. Use mulch to suppress weed growth and to reduce the need for chemical controls.
In early spring before new growth begins, remove the previous year's foliage. You can use hand clippers, a mechanical weed whacker or other power equipment. Grasses will begin growing earlier if foliage is removed and are more attractive when dead foliage is not interspersed with living tissue.
Most ornamental grasses can be propagated by division. Division is also a technique used to rejuvenate plantings. If the center of the clump shows little or no growth, the plant should be divided. Separate and replant the vigorous growth on the outer edge of the clump. Some grasses can be propagated by seed, some of these can become weedy.
Some of the most popular groups of ornamental grasses for warm climates are Miscanthus, Panicum (switchgrass) and Pennisetum (fountaingrass).
In contrast to other flowering perennials, ornamental grasses require minimum maintenance and many species are both insect and disease resistant. However, improperly sited plants may become diseased because of poor air movement, high nitrogen soils or inadequate light.
For low maintenance with a flair, ornamental grasses are hard to beat. Good luck and good gardening.
Gene McAvoy is the horticulture agent with the Hendry County Extension Service. Direct your horticulture questions to PO Box 68, LaBelle, FL 33975, e-mail - firstname.lastname@example.org or phone 863-674-4092 or 863-983-1598. You are also welcome to visit the Hendry County Extension Office at 225 Pratt Blvd., LaBelle. Office hours are from 8:00 - 5:00.
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