What can you tell me about disease problems in impatiens. I grew them this year in Pennsylvania, but they died at the end of the season. Can I replant impatiens in the same place next year?
Impatiens downy mildew is a disease which has been around since the 1800s, but it’s a mystery why it’s become an epidemic across the country. The South has been hit the hardest by the disease. Even though spores can live in the soil, most of the scientific evidence points to airborne spores infecting impatiens. That explains the problem hitting the Midwest and East at the end of the season. The airborne spores are virulent and growers are very aware of the disease and anything bought at the nursery will be disease free. It’s a good idea to treat impatiens like tomatoes, which are also prone to fungal diseases. Plant a little later in the season when things warm up, and water at the base of the plant, not from overhead. Treat the plants with an organic fungicide if the weather is wet and humid to try and prevent an infection.
Don’t plant impatiens in mass; mix up the planting with other shade lovers. If one drift gets infected, maybe the others will be spared. If not, at least there are other plants there to take up the slack. ‘New Guinea’ impatiens are immune and even though they stand the sun better than standard impatiens, they will be happy in the shade too.
This is also a great opportunity to try other shade loving annuals next season. Coleus, begonia, torenia, caladium and others will thrive in the same location impatiens enjoy.