Gardening with Different Ornamental Grasses
Grass is the forgiveness of nature - her constant benediction. Forests decay,but grass is immortal.
-- Brian Ingalls
The satisfaction of experiencing ornamental grasses in the landscape is summed up by the world-renowned European garden designer, Piet Oudolf, when he says “The use of grasses in gardens exemplifies the inspiration of nature.” Grasses evoke the natural landscape because most open, wild environments are dominated by grasses. Simply having grasses in the garden relates the garden to nature and creates a connection with the surroundings.
The popularity of grasses has grown continually in recent decades. Gardeners are recognizing their qualities, especially their long and multiple seasons of interest and low maintenance requirements. They are usually pest-free and disease-resistant (when sited correctly)and perform well in a wide range of different and often difficult environments. Perhaps most satisfyingly her e in Southern Connecticut, virtually every species of ornamental grass is not palatable to deer.
Because ornamental grasses move with the slightest breeze they add a dimension of motion to the landscape. Tall grasses also rustle in the wind, adding sound as well.
Miscanthus, Japanese Silver grass, and its large number of varieties has been widely-used. It features a large and attractive silhouette, delicate seed heads in fall, and remains one of the best grasses for winter interest. However I feel that it has become overused, and can become overbearing in smaller landscapes. It is considered invasive however I have yet to see that in Connecticut where the season may be too short and the climate too cold for it to self-seed.
In a border, grasses can be used as edging or background plants, while larger specimens can be accent plants or screens. A practical aspect of ornamental grasses is to use them as fillers between shrubs, while waiting for shrubs to grow to a more mature size. After 3 years when the shrubs are of a more mature size grasses can be removed, divided and used elsewhere.
Over the past five years or so, there has been resurgence in the interest and availability of native North American species and introductions of new cultivars. Native grasses provide nest sites for meadow birds, as well as food, cover, and shelter for a wide variety of animals. In the garden, they offer textural contrast, and fall and winter interest. There are many native grasses with ornamental features (colorful plumes and seed heads, fine-textured leaves, and fall and winter color). Here are some native non-invasives that I like:
- Prairie dropseed (Sporobolus heterolepis): This an elegant grass that is for perennial borders as well as for mass plantings. It has thin leaves and tall and wispy inflorescences with a fine-textured panicle of tiny flowers and seeds. In the fall the grass turns a striking apricot and orange color. It is a bit slow-growing so be patient for the first few years. Give it enough room to mature and develop fully.
- Little bluestem (Schizachyrium scoparium) is a highly ornamental grass that deserves to be used more. Little bluestem is a dominant grass of mixed-grass prairie. Little bluestem thrives in poor or rocky soil, where it grows into a neat column. In rich soil, however, it grows tall and floppy. In fall, the grass turns reddish-gold, with fluffy white seed clusters. Its gold color and columnar form persist all winter. 3' tall.
- Muhly grass (Muhlenbergia capillaris). This grass has beautiful seed heads in autumn that look like fluffy pink clouds. When it performs well, it is sure to bring visitors to inquire about it.
- Northern Sea Oats (Chasmanthium latifolium) is one of the very few tall grasses that can grow well in shade. About 30-36” tall, it produces open flower clusters in late summer followed by flat persistent seed heads that become showy in autumn.
- Palm sedge (Carex muskingumensis). Another good performer for shade, this visually interesting low grass (20”) has numerous upright stems with whirls of light-medium green leaves.
- Switchgrass (Panicum virgatum). Switchgrass is from the tall-grass prairie and forms tall, stately clumps. In early fall the straight species has airy purplish flower-heads. The seeds provide food for birds. There are numerous desirable cultivars with features that range from foliage that turns red in late summer (Shenandoah), to silvery-blue foliage (Heavy Metal and Dallas Blues) to the extra tall ‘Cloud Nine’ with enormous cream-colored seed heads on 6-foot stems.
The foliage of most grasses should be cut down and removed either in late fall or leave for winter interest and cut them down in early spring. A 10-10-10 fertilizer may be applied at a rate of 1 pound per 100 square feet. A good deal of calcium and magnesium is lost when removing foliage, therefore a soil test for deficiencies of these elements should be carried out periodically and recommendations followed. Do not over-fertilize ornamental grasses, as this can lead to weak stems and disease problems.
