© Janet Davis
Two decades ago, if you
talked about “grasses for the garden”, people would have assumed you were
referring to lawn grasses like Kentucky bluegrass or red fescue. Back then, no one could have 
imagined the huge
increase in popularity of ornamental grasses, long the forgotten child in
horticulture, given that their feathery flowers don’t readily compare with the
colorful blossoms of other perennials. So it’s our great good fortune to have
such a rich palette of these plants available to add a sense of texture,
movement and sound to our borders.
The beginning of the
movement to use grasses dates to the mid-80s and, in particular, the work of
Washington, D.C.-based landscape architects Wolfgang Oehme and Jim van Sweden.
In 1987, I heard them give a lecture called “Brave New Gardens,” about the
revolutionary landscapes they were designing for the broad boulevards, parks
and public buildings of the U.S. capital.
They used huge drifts of certain perennials, many of them native plants,
to give four seasons of interest. At the time, people thought of perennials as
plants that died back in winter, so the notion of leaving the skeletons to
provide interest when the snow came was a new one. But that’s what Oehme and van Sweden did, mass-planting
throughout Washington thousands of blackeyed Susan (Rudbeckia fulgida
‘Goldsturm’), yarrow, astilbe, sedum 
and (especially big
stands of lush ornamental grasses like maiden grass (Miscanthus sinensis),
switch grass (Panicum virgatum) and feather reed grass (Calamagrostis
acutiflora).
Ornamental grasses are being used extensively in designs at botanical gardens throughout North America, giving gardeners lots of great ideas for deploying them in their own landscapes. At the Chicago Botanic Garden, the Native Plant Garden demonstrates how to use native grasses with native forbs (wildflowers). Northern dropseed (Sporobolus heterolepis) has airy flowers and seedheads that look gorgeous with purple coneflower. In another area, switch grass (Panicum virgatum) nestles beside flowering spurge (Euphorbia corollata) and wild quinine (Parthenium integrifolium), and in the demonstration prairie itself, visitors can check out big bluestem (Andropogon gerardii) and see how wonderful it looks alongside prairie daisies like compass plant (Silphium laciniatum) and cup plant (Silphium perfoliatum). At the Montreal Botanic Garden, architectural grasses like Molinia caerulea ssp. arundinacea ‘Skyracer’, Korean feather reed grass (Calamagrostis brachytricha) and variegated eulalia grass (Miscanthus sinensis ‘Variegatus’) make dramatic statements in many unusual and artistic gardens. And at the Royal Botanic Garden in Burlington, Ontario, colorful daylilies are used as a foil against the lush foliage of Miscanthus sinensis varieties in the Monocot Garden.
I’ve used grasses
extensively in my own garden. A few
years ago, I replaced my front lawn and much of the shrubbery with a large
“prairie” planting that performs beautifully in summer 
drought. Along with
wildflowers such as Penstemon digitalis ‘Husker Red’; purple coneflower,
rudbeckia ‘Goldsturm’; choice goldenrods like Solidago sphacelata ‘Golden
Fleece’; great blue lobelia (Lobelia siphilitica) -- a fabulous plant:
New York ironweed (Vernonia); artemesia ‘Silver King’ and blazing star (Liatris),
I also incorporated three types of ornamental grasses. The first, little bluestem (Schizachyrium
scoparium), is a two-foot-tall native of the tallgrass prairie that begins
in the U.S. Midwest and stretches into Southwestern Ontario. It has narrow,
steely blue leaf blades and silvery flowers in late summer, when it turns deep
cranberry-red. Alas, in my own garden,
the soil is not sandy enough for this little grass and it has not thrived. The second is switch grass (Panicum
virgatum ‘Rehbraun’), another tallgrass prairie native that grows to about
four feet with wider leaf blades and airy flowers with zingy little grains that
look spectacular as a screen in front of blackeyed Susans, for example. As its
name suggests, the leaf blades of ‘Rehbraun’ colour to red-brown in late
summer. The third is maiden grass (Miscanthus
sinensis ‘Gracillimus’.). Like a lush green fountain, it rises to 4-5 feet
in height, and stands up well through winter – until a big wet snow or freezing
rain or freezing rain knocks it down.
Ornamental grasses should be cut back in early spring. The ones mentioned here all prefer a sunny site.
Adapted from a column that appeared originally in the Toronto Sun