The wet, humid summer has created perfect conditions for a disease called downy impatiens mildew. Even though it's been around since the 1800's, for some reason, it's become virulent over the last several seasons.
It only affects Impatiens walleriana and no other impatiens species. This story details how the disease is spread and how to deal with it before it strikes.
Basically it starts in the south as airborne fungal spores and works its way north to infect our plants. The weather has helped and now in my garden the plants are losing their leaves and collapsing.
I've planted the garden with plenty of other shade lovers including torenia, caladiums, begonias, New Guinea impatiens and more, but still plant standard impatiens and enjoy them until the plants give up the ghost.
I should have been treating them with an organic fungicide before signs of damage emerged, but hindsight is 20/20, right? One the plant is infected, it's doomed.
There are plenty of plants left in the garden and they will get sprayed with Serenade, my favorite organic fungicide.
The impatiens have put on a show since May and the only one to blame for their demise is this gardener.
Hopefully I'll save what's left.