On the Garden Path: Ornamental Grasses

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Photo by Ajale/pixabay

Grasses belong to one of the largest and most varied families in the plant kingdom. Recently, different grass varieties are being incorporated in landscape plantings. Several reasons exist for this trend.

First, ornamental grasses not only beautify the landscape, they also play an important role in conservation. Second, they require lower applications of nitrogen and pesticides. Third, some grasses are so hardy that they tolerate drought, wetness and fluctuating temperatures. Fourth, ornamental grasses are resistant to most diseases and insect pests. Because of these characteristics, gardeners interested in attractive, low-maintenance or sustainable landscapes choose ornamental grasses.

These grasses can be utilized in a variety of ways because they differ in size, shape, color, texture, foliage and seed heads. Heights of mature plants range from 6 inches to 14 or more feet tall. Foliage colors include yellows, greens, blues, reds and browns, as well as a mixture of the colors.

Many ornamental grasses change colors during seasons. For example, fall may produce such colors as yellow, orange, red or purple, enhancing areas with bold contrasts. This will remain during winter, providing color in an otherwise barren landscape.

Ornamental grasses serve many landscape functions. They are known for adding life, motion and sound to gardens. In fact, plantings may resemble an inland sea during windy days, with movements creating rustling sounds. However, because grass covers the surface of the soil, with its roots holding the soil particles together, erosion cannot take place.

These same grasses may also be utilized as edging or backgrounds for other plantings, such as shrub roses or black-eyed Susans, and they are capable of stabilizing banks by serving as ground cover. Some of the shorter grasses work well in rock gardens.

A solution to creating drought- and pest-resistant plants is through providing for the fibrous – threadlike – roots. Adding organic matter improves water-holding capacity, breaks up compact soils, maintains oxygen levels and allows for necessary root expansion. Improving soil will result in less maintenance and will minimize plant loss.

Ornamental grasses may be annual or perennial. Annual grasses, usually planted in the spring, die at the end of the growing season, and new seed must be planted. However, if irrigation is available, container-grown ornamental grasses may be planted later. Perennial grasses live through the winter and grow again each year. In the Midwest, bare roots or divisions must be planted in the spring.

In contrast to perennials, annual grasses require minimum maintenance and are often disease- and insect-resistant. Dangers do exist in planting grasses where there’s poor air movement, in high nitrogen soils, or where there’s inadequate light. Most varieties of these grasses require sunny, well-drained areas, but some will adapt to wet soils.

Tests for phosphorous and potassium levels, as well as pH and soluble salts content, should be administered before planting ornamental grasses. These tests should be done every five years. If soil is lacking necessary nutrients, incorporate them into the soil before planting. Applying nutrients to the soil’s surface is not advisable because nutrients do not always move to the root system where needed.

Foliar appearance is a guide for what grasses need. If a leaf blade lacks color, nitrogen or a micronutrient should be added. This condition may also indicate low soil oxygen levels, inadequate drainage or excessive watering. Newly planted grasses require a moist root zone. Drip irrigation on plants works well. Do not water drought-resistant plants too often. As grasses grow, the moisture required depends on the species, soil, wind and heat from the sun. In turn, amounts of moisture determine quality, growth rate and size.

Weed control is essential for most ornamental grass plots. Preparing a weed-free planting site will eliminate many problems. Herbicides eliminate dandelions, plantain and other broad-leaved weeds, but selective herbicides are not available for grassy weeds among ornamental grass plantings. Mulch will also suppress weed growth.

Maintaining ornamental grasses is fairly easy, but removing last year’s foliage with hand clippers or other equipment is necessary for continual growth. Because dead foliage hinders growth, separate plants from dead growth and replant the vigorous growth from the outer edge of the clump.

Both native and exotic grasses are suitable for Midwestern plantings. The native grasses, such as bluestem, were part of Midwestern flora before European settlement. Through settlement, some grasses known as exotic were carried from Europe.

Today’s popular grasses include fescue, switchgrass and fountaingrass. Select these carefully to insure hardiness and adaptation to environment.

Fescue is a cool-season, clump-forming grass. Blue foliage forms are the most popular. Early spring divisions are necessary for a vigorous growth. Miscanthus is a clump-forming grass with showy flowers. Types of this grass vary in height and blade width. Switchgrass is another warm-season, clump-forming grass that has recently become popular with its red or blue foliage. Fountaingrass is a warm-season, clump-forming, dark-green grass that produces foxtail-like flowers that turn from white to creamy tan.

Additional perennial ornamental grasses include blue lymegrass, blue oat grass, feather reedgrass, flame grass, Japanese grass, moorgrass, palm sedge, ravennagrass, red switchgrass, ribbongrass and silver variegated Japanese sedge. Annual ornamental grasses include squirreltail grass, feathertop, purple fountaingrass and rubygrass pink crystals.

Grasses are found on almost all land surfaces of the earth, such as in swamps and deserts, polar regions and tropical areas, rocky land and snowy mountains. With care and careful selection, ornamental grasses can be part of your landscape, bringing about beauty and contrast.