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Fireworks in the Garden!

© Mary Henry

Fireworks in the garden? Or maybe they are fountains. Anyway, that's what the flowers of the ornamental grasses look like this time of year. Rising up out of their imposing clumps and arching over into the sunshine. Their subtle colors and gossamer sheen are stunning against a blue sky. Such a celebration is a fitting fanfare to the glories of the fall garden.

Those of us in the prairie states have always taken grass too much for granted. We were slow to welcome it into an ornamental place in our gardens. It took exotic introductions from overseas to wake us to the possibilities at hand, but now we seem to be getting it. I see more and more being used all the time. I'm even finding places for some of the smaller ones in my tiny yard. Now if there were just more sun...

One question that comes up again and again at the garden center is "Can I grow Pampas Grass?" Here the answer depends entirely on what you mean by "Pampas Grass". Technically it is Cortaderia selloana, a native of the Pampas in South America that has even become a naturalized nuisance in California. It never will in Minnesota because it must be grown in a pot or as an annual if at all. Instead, we have our own escaped alien that somewhat resembles the true thing: Miscanthus sacchariflorus or Chinese Silvergrass. It is a beautiful, if stealthy, thing that can send its creeping stems everywhere that isn't under concrete, so you'd better like it a lot. A much better choice is Miscanthus sinensis 'Silberfeder', Japanese Silvergrass, as polite as its namesake culture. I like its big, broad fountain of a clump better anyway.

It has been tough to get nurseries to stock many ornamental grasses here, because very little was known about their winter hardiness. Most of the zone assignments were approximate and mainly based on someone's best guess. In the late 1980's the Dept. of Horticultural Science at the University of Minnesota planted 165 varieties or ornamental grasses at the Minnesota Landscape Arboretum in Chanhassen. The plants were set out in the open and mulched with wood chips over landscape matting to control weeds. They were watered to establish them in their first year and given a dose of organic fertilizer in midsummer. Then all the researchers did was keep notes on their progress and condition. After six years, they discovered that 85 of them were fully hardy and could be expected to thrive in our gardens. Another 35 survived for four or five years and can be considered marginally hardy for the gardeners who like to test their microclimates.The rest survived two years or less, so save your money there. The Bulletin, Ornamental Grasses for Cold Climates that came from the research is worth its money though and can be ordered here.