Impatiens downy mildew can over winter in flower bed and containers
Cydney Steeb column (March 20, 2013)
According to both Michigan State University horticulture and Grower Talks Magazine, there is evidence that this downy mildew pathogen may over winter in garden beds and containers and could affect impatiens planted in beds with a history of this disease. I should mention that Grower Talks Magazine is a horticulture industry magazine you're not likely to find on any magazine stand or in a bookstore.
Torenia is also called the wishbone flower and comes in shades of blue, purple, pink and yellow. Several years ago I spotted torenia at a local nursery and decided to plant it along the top of a stone retaining wall so it would cascade down over the wall. We experienced a late frost that year which caused major damage and I lost many of my annuals. I thought I had lost the torenia, but about a week later I saw new growth at ground level. The plants made a full recovery and I have included them in my garden design every year since.
I have had several gardeners ask my opinion on planting impatiens walleriana this year. My answer is that I am not planting this variety of impatiens even though my impatiens did not have the disease last year. I was lucky. I plan on waiting at least a year to see if the disease presents itself again. I don't want to waste money on plants I'll have to throw out and take the chance on bringing the disease into my garden.
If you're a gardener who insists on planting this impatiens variety and you had the disease last year, MSU says to be sure to clean up all diseased plant material and mulch from the area. Be sure to bag it, DO NOT COMPOST, and dispose of with trash. If your neighbors had the disease in their flower beds, encourage them to do the same as the spores are spread by wind.
Take a chance and try something new this year. If you like to cook with fresh herbs, convert one of your hanging baskets or containers into an herb garden. The herbs will be close to the kitchen and you'll be more likely to use them. I saw a beautiful herb basket in a magazine. They used rainbow chard for the tall thriller, varieties of thyme, and mint for spillers and a variety of short herbs for fillers. I like to include nasturtiums for color, and you can add the flowers to salads.
By the way, happy spring! Yes, Mother Nature does have a sense of humor. One year ago today we had a high temperature of 82 degrees.
Cydney Steeb, Advanced Master Gardener, can be contacted at Emmet Conservation District, 3434 M-119, Harbor Springs (231) 439-8977 or email@example.com. Her Gardening Wit and Wisdom column runs every Wednesday.