Dowy mildew killing impatiens

Starting in late October each year, Palm Beach County, Fla., enters a colorful phase as millions of impatiens are planted to jazz up the entrances of gated communities and add punch at shopping centers, banks and resorts.

But this year there's trouble with the flowers known for their hues of coral, orange, pink, red, lavender, purple and white. After early January's damp cold snap, landscapers and their clients began noticing that the impatiens were dying. Now countless plants have been ripped out, costing homeowners associations extra thousands and even bigger money for a multimillion-dollar flower business that blooms when snowbirds visit.

The culprit? The impatiens were the victims of a disease called downy mildew that caused problems elsewhere in the United States last year and has been wiping out impatiens in Europe and South Africa.

The Gardens Mall replaced its impatiens with white begonias.

At BallenIsles, a country club community in Palm Beach Gardens, the 500 or so impatiens in the master areas were replaced with other flowering plants such as begonias, lobelia and osteospermum, said Carol Cloud Bailey, property manager and horticulturist for the community association.

"We had a lot of residents who planted impatiens at their homes. It has been quite devastating for them," she said.
Valerie Bass, owner of Bass Nursery in suburban Lake Worth, disposed of 8,000 infected plants last month.
"It's so depressing to have to tell people," Bass said. "I keep saying it's the end of an era. None of the nurseries are growing them for next season."

Plasmopara obducens, the type of downy mildew that's killing the impatiens, attacks only the Impatiens walleriana, which is most prevalent here. Two less common varieties that are more expensive and aren't available in as many colors, SunPatiens and New Guinea, are not susceptible.

Impatiens are the nation's and Florida's most popular bedding plant, according to the University of Florida.

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For more information on how to treat for downy mildew, click here.