A bevy of benefits
Ornamental grasses are also largely unaffected by diseases and pests, resulting in better survivability, improved and consistent appearance, low pest control costs and reduced maintenance budgets. Their deep and fibrous root systems discourage gophers and other tunnelling animals. Grasses also improve soil conditions and fertility, even without supplemental feeding and can provide seeds for birds and other wildlife.
In addition, ornamental grasses can be used to create buffer zones for water features. In many cases, constructed wetlands have used large areas of reeds as small-scale sewage treatment systems. This demonstrates the significant filtration benefits of many grasses, which has subsequently led to the extensive use of grasses in swimming ponds. The right blend of grasses can produce a clean and safe environment in which to swim, without the need for chemicals and labour-intensive manual cleaning. The result is a visually attractive water feature that rivals a swimming pool, with significant environmental and health benefits.
Further, ornamental grasses can be used to stabilize slopes and waterfronts because their often extremely dense root systems are able to hold large masses of soil in place. In terms of shape, their upright form tends not to take up as much space as most shrubs, trees or more traditional perennials. Mixed with broadleaf annuals or perennials, they can add stunning texture, colour and size, whether large or small.
Ornamental grasses are low-maintenance plants, requiring only a spring cut-back. It is best to cut off blooms in early spring and cut the entire plant down to a height of approximately 80 to 100 mm (3 to 4 in.). This allows substantial new growth at a time when the plant will not be harmed from being cut, while ensuring the old, unattractive foliage and blooms from the previous year do not get mixed in with the new growth. While cutting blooms or foliage in the fall will not necessarily kill the plant, it can cause long-term damage and is therefore not recommended.
Ornamental grasses also have very low nutrient requirements. In fact, some become less healthy as soil nutrient conditions improve. (The aforementioned northern pampas grass is one such example.) They require little, if any, fertilization and are largely unaffected by poor weed control. Also, very few species are invasive in Canada. The varieties that do spread need not be avoided; instead, they should be planted selectively. Choose areas in which a substantial amount of the same grass species will be visually attractive and where the spreading nature of the plant will not cause issues with neighbouring plant material.
Most ornamental grasses are ‘clumpers,’ meaning as they grow in height, they will also grow in breadth. If left too many years, their breadth will expand such that the centre of the plant will begin to die out. At this stage (or before), the plant can be dug in the spring, divided rather aggressively into three or four plants and replanted. This, effectively, is how they reproduce. Many natural grass species spread by seed, causing them to be incorrectly labelled as invasive or simply undesirable. However, where this is the case, a perfectly suitable cultivar without the same spreading tendencies can usually be found.
A growing trend
The few compromises and disadvantages associated with ornamental grasses make them a visually interesting, versatile and beneficial option in any landscape design. Armed with the right knowledge, landscapers will no doubt continue to incorporate these unique plants into their designs.
Sue Dyer is the owner of Kings Creek Nurseries in Ashton, Ont., near Ottawa. She can be reached via e-mail at email@example.com.