Many of you who have gardened in the last few years are familiar with a plant disease called powdery mildew. This disease causes a white powder to form on the leaves of the plant.
If you grew squashes or roses, you probably saw it on your plants. There is another mildew that you will need to be aware of if you plant impatiens in your flower beds.
Downy mildew is a disease that has been around for years, but it has not shown up very often in gardens. However, in the last year, a particular strain of downy mildew has attacked impatiens. When it infects impatiens, it causes discoloration of the leaves and ultimately it causes the leaves to fall off. Ultimately, you wind up with just the stems. There are sprays that you can use, but they are not effective unless you apply them diligently all season. Even then, the disease may start and once it starts, it will decimate the plants.
The reason I am telling you this is that many of the growers are going to drastically cut back on their number of impatiens in 2013. Some growers have decided to stop growing regular impatiens.
The reason is economics. If they need to continually spray the plants while they are growing, then any profit they would make from growing the plants is used up by the cost of the fungicide and the cost of its application.
Your first thought may be to make sure to get your impatiens early before the supply runs out. On the surface this may seem like a good idea, but then you will have to do the fungicide treatments of the plants to possibly no avail. It is probably a better idea to think about planting some other shade loving plants until there is an effective way to control this disease.