I planted several flats of impatiens, which have done for 10+ years. They were doing great. . .then started looking sickly and dying off. Only the stems are left. I went back to the greenhouse I purchased from, they weren't of much help. First, I was told root system was fine, and I didn't water enough, then I was told I watered too much. I live in Syracuse, NY and we have had a hot summer, but it has been hot in prior years and my flowers were fine. Leaves start to turn light green, then the flowers start to thin out, then just the stems are left.
My Impatiens Are Dying
Certified GKH Gardening Expert
This article will help with pinpointing the likely cause of the plants' demise: https://www.gardeningknowhow.com/ornamental/flowers/impatiens/impatiens-problems.htm
Just in case you cannot save them, you may want to take some cuttings (provided you still have some healthy foliage). They propagate easily and this way you can continue to enjoy them. This article will help: https://www.gardeningknowhow.com/ornamental/flowers/impatiens/impatiens-rooting.htm
sounds like some sort of insect infestation like spider mites did you try spraying them? (I don't really like using insecticides, but sometimes you have to take drastic measures) JenJM