Each week, we pick a question that we get through our Master Gardeners hotline and write an article for the popular, online magazine Rural Intelligence. Below is this weeks article.
Impatiens are an annual favorite: easy to grow, shade tolerant, and for the most part, a great bang for your buck. Normally, this time of year you could walk into any garden center and find tables that are filled with what seems like endless flats of their pink, white, red, and purple blooms. So what gives? Why doesn’t anyone seem to be carrying this go-to container plant this year? Nurseries across the area just don’t seem to have them and for good reason. It’s all due to the fungus Plasmopara obducens, better known as Downy Mildew.
Sometime in 2011, Downy Mildew started showing up in the Northeast and by 2012 it was everywhere. It affects the variety walleriana, which, for the most part, is what you have been buying at your local garden center for as far back as you can remember. The disease works something like this: Your leaves start to look yellow or mottled, with some getting a white “downy” growth on the underside of the leaves. The leaves eventually fall off leaving you with leggy stems that result in a total collapse of the plant. It ain’t pretty.
Sound familiar? Did it happen to you last year? It’s likely — and if it did, you really should avoid planting them again this year. Let’s face it — impatiens have been done to death. This is your chance to break free! Use this as an opportunity to plant something new that you haven’t tried before. Begonias, fuchsia, caladiums, coleus, salvia, oxalis — all are great, shade-loving alternatives with nice growth habits and there are so many others out there. Who knows, maybe this time next year you will have forgotten all about impatiens.
If you absolutely have to have them, however, and still want to give it a go, here’s what you should do: If you grew Impatiens last year, plant them in a different location. This disease is not only airborne, but the spores stay in the soil as well. If you planted them in containers, dispose of the dirt (not in your compost pile) and disinfect your container with a bleach/water mixture. If you do notice some of the mildew symptoms, immediately pull up the infected plant (roots and all), put it in a plastic bag, and get rid of it.