Every gardener I know has been a mess over the trouble with old-fashioned Impatiens (Impatiens walleriana). For many decades these colorful flowers adorned the shady spots of gardens around the world. They were one of, if not the easiest annual to grow for most gardeners and we loved them. Then the trouble started.
Around 2008, a few gardeners noticed their impatiens getting sick and dying. Then a lot of gardeners noticed the same. Impatiens walleriana started dying, not just all over the country, but all over the world. A disease called Impatien Downy Mildew had managed to infect plants everywhere in a very short period of time. The bedding plant that was once the easiest and most reliable color for decades was suddenly almost impossible to keep alive.
The disease was quickly identified due to its visual impact. Leaves initially turn yellow, then become covered in a fuzzy white coating on the undersides. Finally all the leaves drop and the plants die. There is no effective treatment to cure infected plants and the disease can spread easily. The disease can even persist in the soil for years, waiting for more impatiens to arrive to be infected. Luckily the disease only affects Impatiens walleriana so everything else in your garden is safe from this pesky problem.
Many in the plant industry stopped carrying Impatiens walleriana because it was too hard to keep them alive in the nursery. There was also hope that if everyone stopped selling and planting Impatiens walleriana, in a few years the disease might die off from a lack of host plants to infect and our soils would be clean again. This plan has proven ineffective.
After years of abstaining, Tallahassee Nurseries tried these plants again only to find the disease present and just as damaging for our own stock and the gardens of our customers. Tallahassee Nurseries is committed to selling healthy plants that have the expectation of thriving if given proper care. As such, we have made the decision not to sell Impatiens walleriana since we know most of them will fail to thrive in our climate.
We have heard a few reports of people still successfully growing Impatiens walleriana in their gardens. These are, by far, rare exceptions to the experience of most southern gardeners.
Gardeners can still find Impatiens walleriana for sale at some garden centers. These businesses have looked at the same information we have and come to a different decision about what product to carry. The decision to sell, buy, or plant Impatiens walleriana is a personal one. The more these plants are used the more the disease will spread and the longer it will persist. If you have a garden that has not yet been touched by the disease you are very lucky, but each time you plant them the likelihood grows that the disease will appear.
For the time-being, we have to find alternatives for these colorful shade plants, but the future is promising. A plant breeder in the Netherlands is actively developing a series of Impatiens walleriana that has a “high resistance” to Impatiens Downy Mildew. Countless other breeders have been searching for such plants but the hunt has been without fruit until recently. These plants are still being researched and developed further, but they are showing great promise of being able to bring the world’s favorite bedding plant back to gardens all over. Combined with proper care and disease reducing garden practices, these plants may be happily growing in your very own garden in the next 3-5 years.
Alternatives to Impatiens walleriana for color in the Shade
Check out these articles from knowledgeable and reputable sources, for more information on Impatiens Downy Mildew. This information will help you make your own decision about whether you should grow Impatiens walleriana in your garden.
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*This article was written by Jonathan Burns (Tallahassee Nurseries Outdoor Manager, FNGLA Florida Certified Horticulture Professional) using information published by the University of Florida combined with years of personal observations growing in the Tallahassee area.