Ornamental Grasses

Marg Hundt

Ornamental grasses can turn any garden from ordinary to spectacular. Whether it is a gravel garden, Asian style, or patio display, bamboos, grasses and grass-like plants can make it special.

Grasses form the dominant vegetation across great swaths of the earth including the African savannas, North American prairies, Russian steppes, and South American pampas. They can survive on little water and grow from the stem and leaf bases, so they are able to withstand damage. True grasses are in the Poaceae family also known as Gramineae, and include lawn grasses, cereal grains and showier species grown as ornamental garden plants, as well as bamboo.

Grass has become a convenient way to identify a range of plants including sedges, rushes and cattails. "Sedges have edges, rushes are round; grasses are hollow and rush all around". True grasses have narrow leaves with long straight veins running parallel to the leaf edges. Their cylindrical stems are hollow, except at the solid joints, called nodes. Cattails are aquatic or marginal plants in the family Typhaceae. They have flat, narrow, iris-like leaves and distinctive velvety-brown, cigar-shaped flowering structures. Their stems are solid. Rushes are grass-like plants that belong to the family Juncaceae. These stems are typically cylindrical, like those of true grasses, but they tend to be solid rather than hollow and lack nodes. Sedges are in the family Cyperaceae. They also lack nodes and have solid stems that are triangular in cross-section.

Grasses are masterpieces of structural engineering and despite being so thin, they carry their leaves well above the ground and are quite elastic when swaying in the breeze. Large numbers of long, narrow, thick-walled cells called, fibers, support their stem tissues. At the nodes inside the tube-like stem, the cavity is filled with reinforcing plates to prevent buckling when the stems bend.

Grasses can add an exotic touch to traditional gardens. Because of their diversity of colour, shape and textures and the fact that most need very little attention, grasses and bamboos are ideal plants to accompany the sleek lines and cutting edge material of modern gardens. They are suitable to low-maintenance designs and grow well in gravel. Chinese and Japanese gardens are an oasis of green in which rocks and gravel, water and plants are combined to create an idealized picture of nature. The effect relies on the juxtaposition of foliage, shape and textures. Planting a border with just grasses can provide year round interest and be surprisingly colorful, with a sense of movement that shrubs or perennials simply cannot match.

The flower can form a simple spike- a narrow, unbranched structure with the flowers attached directly to the central axis; a raceme (where the flowers are attached to the central axis by a short stem call a pedicel); a panicle (an inflorescence that has side branches) or an awn (where the bloom extends beyond the leaves).

Grasses depend on wind, rather than insects to carry their pollen from flower to flower. Many grasses form clumps that expand slowly over time and stay where you put them. Others are creeping grasses and produce vigorous horizontal stems that extend out over the ground or below it and still others pop up here and there, often far from the original plant. You can control their growth with root barriers a foot or more deep or by smothering the previous season's seed before they sprout with mulch; hoe or pull unwanted seedlings or, remove the flower head before the seeds ripen (but you lose interest and beauty). Remember the adage: the first year they sleep, the second they creep and the third they leap!

Grasses can suit any spot from a balcony to a large landscape. They range from inches to 20 feet. They can be tufted, mounded, upright or a combination shape. Their colours vary from green, yellow, brown, pink, maroon or silver. Some change and mature, turning tan, brown, gray or gold.

There are annual grasses and perennial grasses. Perennial are classified as cool season- they start growing in late winter or early spring and flower in spring and early summer and, warm season grasses that thrive in the heat and start growing later in the spring and flower and set seed late summer or fall.

Gardeners obsess with light - morning, afternoon, full sun or shade! With grasses the beauty comes with the direction of light. When illuminated from the side or back either with sunlight or landscape lighting you will enjoy the distinctive shapes and texture of leaves, flowers and seed heads. The effect can be a silhouette or look like stain glass.

When fine-textured grasses are planted next to big, bold leaves, it adds an eye-catching contrast. They are invaluable to soften "hard scape" such as walls, paved areas, steps, boulders and other solid surfaces. Combining similar textures creates a restful feeling while combining different textures creates a very dramatic effect.

When buying, choose wisely. Consider zone, humidity, coastal conditions, soil quality, moisture, colour, texture, height, how much maintenance, and if they are spreading or clumpers Plant cool grasses anytime. Plant warm season grasses in early spring so they can put down roots. Space about as far apart as the mature plants will be tall and water regularly during the first year to establish the root system. Leave foliage intact to protect the plant's crown from cold. In the winter you can enjoy the beauty of seed heads and the wild birds will take shelter and eat seeds. Cut down to 4-6 inches in late winter or early spring.

Rust, aphids and mealybugs may attack your grasses, but generally they are quite resistant to disease.

I am always amazed at the resilience of the grasses to stand straight up again after a strong wind blows them flat on the ground. I love grasses. The swaying in a gentle breeze is a wonderful mellow, restful feeling and worth the effort of growing