The most familiar lawn grasses can not do what the many other grasses and grass like plants do in a garden. Lawns are mown into submission so that they can function like carpet in outdoor rooms. They certainly have their appeal and practicality, although they require very regular maintenance and generous watering.
Other ornamental grasses are grown like more common perennials, to provide appealing foliage, flowers, forms, textures and ‘motion’ as they move in even slight breezes. Most require significantly less water and maintenance than lawns do. Sedges, rushes and papyrus, although not grasses, function like grasses around ponds and in areas that are too damp for grasses to be happy.
Giant reed, pampas grass and bamboo are all notorious as invasive weeds. Giant reed and pampas grass appear and grow voraciously in some of the worst places that their seeds can get into. (Giant reed should not be planted anywhere near waterways or riparian environments.) Bamboo is not nearly as prolific, but spreads aggressively by stolons (subterranean stems) that grow very fast and potentially reach several feet.
However, where they can be contained, these three are the boldest of their kind. Giant reed grows like large types of bamboo, but fluffier, with broader undivided leaves. Pampas grass develops into big mounds of graceful foliage with billowy white or pinkish flower plumes. (Pampas grass leaves can cause nasty paper cuts, though.) The many different types of bamboo provide a variety of graceful foliage; and many provide striking form with their rigid canes. Some bamboo are low and compact. Most are tall and elegant.
Dwarf blue fescue is among the smaller ornamental grasses, forming round tufts of soft but seemingly bristly blue foliage that resembles dense bundles of pine needles. Fountain grass is considerably larger, with green or purplish foliage, and flower plumes that look like kitten tails. Hair grass is so softly textured that it barely supports its own weight, and often lays gently on the ground or leans onto other plants.
Except for giant reed, pampas grass and the various bamboos, most ornamental grasses do not need much attention. Some look better if they get cut back before they start to grow at the end of winter. Others should get their fading flowers removed. A few are deciduous, so die back over the winter. Grasses are otherwise easier to care for than any lawn and many other perennials.
To avoid confusion with dwarf fescue blue turf grass, Festuca ovina glauca is more familiarly known as blue festuca. If planted close together and left to spread as a small scale ground cover, it is much lumpier and mounding than uniformly spreading turf. It is a clumping perennial that is more popularly grown as distinct tufts of finely textured blue gray foliage that looks like gray sea urchins.
It was probably a good idea when it was introduced to California, but fountain grass, Pennisetum setaceum, became too much of a good thing for a few temperate regions in which it naturalizes and displaces native vegetation. Although it now works to inhibit erosion where it grows wild on the embankments of highway interchanges, it must sometime be mown because it is combustible.
Modern garden varieties of pampas grass found in nurseries are generally non-invasive. Their flowers are described as ‘sterile’, and therefore unable to produce seed. What that really means is that they are exclusively female, and unable to produce seed without male pollinators. However, they have the potential to be pollinated by naturalized pampas grass, and sow a few hybrid seed.
Tony Tomeo 