By Irene Virag
For decades impatiens covered the countryside like Caesar’s legions, ruling the garden with their seeming invincibility.
But even Julius’ legions didn’t last forever. As many of you may well know by now, suburbia’s favorite bedding plant, Impatiens walleriana, is in big trouble. It’s under attack by a downy mildew disease that’s similar to the late blight that attacks potatoes and tomatoes.
But the disease doesn’t just damage impatiens—it destroys them. First the plant loses its blooms, then the leaves go, then the stems topple over and the impatiens is gone. (Photo courtesy of Margery Daughtrey)
The disease has been around for centuries—it was found in North America as long ago as the 1800s—but it’s only in the last few years that it’s been accorded heightened awareness. The damage became dramatic in 2009 in Saratoga Springs, New York, when all the impatiens on the main street and the city’s famous racetrack failed to show. Two years later the mildew struck in 11 states. Last year the number more than tripled, as 35 states were afflicted.
“We first saw it here in the fall of 2011,” says my friend Margery Daughtrey, a plant pathologist at Cornell University’s Long Island Horticultural Research and Extension Center in Riverhead, New York.
The following year the pathogen became a plague. “It kept taking out impatiens all season,” Margery says.
Circumstantial evidence indicates that the disease stays in the soil, although experts don’t yet know for how long.
Margery explains that the virulence is not like powdery mildew; you can see the spores only by looking for a white coating on the undersides of the plant’s leaves. (Photo courtesy of Margery Daughtrey.)
It’s nice to know that the disease is what experts call host-specific; that is it doesn’t go after other flowers or vegetables. But I’m not taking any chances, although I am fond of Fusion impatiens, probably because they don’t look like impatiens.
Michael Chapman, the garden department manager at my favorite Lowe’s in Farmingdale, New York, concurs. “We’re not selling them this year,” he says. “We couldn’t even get them. No one’s left the store crying. We assure them there are other flowers they can plant.”
Indeed there are: You don’t have to wallow in grief if you can’t wallow in walleriana. There’s a bouquet of other lovely annuals out there. There’s even New Guinea impatiens, which are impervious to the dreaded downy mildew, and come in various colors from red and coral to white and lavender. They may cost a little more than walleriana, but they’ll take a bit more sun and are grand on the ground, in pots, and hanging baskets. Or try SunPatiens. Marketed as the sunny cousin of impatiens, it thrives in shade as well.
And begonias. I love begonias in the garden as well as in pot arrangements. Wax begonias, with shiny bronze or green leaves and white, pink, or coral flowers, offer Victorian charm. Dragon Wing begonias, which grow more than a foot tall, provide drama. Cultivars of trailing Begonia boliviensis, such as ‘Bonfire’ and ‘Million Kisses’, add elegance. And tuberous begonias bring instant beauty.
Or give coleus a chance. Its splendid comes in a kaleidoscope of colors and patterns, with marvelous names such as ‘Fishnet Stocking’ and ‘Religious Radish’. And coleus mixes and mingles with begonias, ferns, and other shady characters.
Coleus is vulnerable to a downy mildew, but not the same organism that kills impatiens, according to Margery. “The disease seems to affect different cultivars of coleus to different degrees, causing negligible injury to many cultivars,” Margery says, “and doesn’t linger in the soil from year to year to pounce on healthy plants next spring.” She’s involved in a trial aimed at finding out which coleus cultivars are most resistant.
Torenia, also known as wishbone flower, is another annual that substitutes nobly for impatiens. Or caladiums, with heart- or lance-shaped leaves on long stalks that grow from tubers. And don’t forget fuchsia, with its cascading, lanternlike blossoms.
Another thought is to try perennials such as coralbells (Heuchera) or hostas. There are miniature hostas, huge hostas, and gold-leafed varieties that act like spotlights in the shadiest of shade gardens. Hostas are like the New York Yankees’ star relief pitcher, Mariano Rivera: They’re reliable, and they always come through.
So don’t let the downy mildew get you down. There’s life beyond walleriana. And who knows what the future will bring? When it comes to impatiens, it just may pay to be patient.
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