Downy Mildew Infecting Impatiens
Well, if you haven’t already heard, we have a very unfortunate problem here in WNY (and elsewhere in the U.S.). Impatiens, probably the most popular annual flower for their many colors, price, and ability to survive the shadiest spots, are being infected by downy mildew. Both regular impatiens and double impatiens may be infected (impatiens walleriana), while New Guinea impatiens (impatiens hawkerii) and Sunpatiens are in different enough families that they are unaffected.
The disease is spread through spores in the air, and overwinters in the soil. Basically, that means if your garden beds had the disease last year, it will be there this year too, and if your neighbor had or has it, it may travel on the air and infect your gardens in that way too. Sadly, once an impatien plant is infected, it cannot be cured.
Downy mildew strikes the leaves first, making them appear yellowish, then wilted. Next, the white growth pictured above will show up on the undersides of the leaves. The blossoms fall off and then the leaves fall off, leaving bare stems that will eventually collapse, likely leaving the homeowner frustrated (and wishing they had planted begonias instead).
Some of the best shade options we are recommending this year to replace impatiens include:
- Coleus (click here to get inspired!)
- New Guinea impatiens (if you have a bit of partial sun)
- And of course, wax leaf begonias.
Check out this Shade Annuals Factsheet from Nora Catlin, CCE Suffolk County for other shade annual options. We see this as an opportunity for folks to experiment and get creative with other shade annuals, so please share what you substitute for impatiens in your garden this year!