Echinecia and coreopsis diseased?
Several of my purple coneflower and coreopsis seem to have a disease or something.
I started noticing a coneflower looking droopy, as if it need watering...so I watered. The leaves continued looking droopy and wilted no matter how much water I pour on it. This started with one stalk then progressed to most of the stalks until the leaves and stalks are now have a blackish tarrish look. I eventually had to cut the bad stalks down, but I noticed the good stalks just came right out of the soil with a gentle tug. Right now couple other coneflowers are looking the same but several others are nice and lush and filled with lovely blooms.
I also noticed one of my coreopsis having a wilty look. I just now gave one of the bad stalks a gentle tug and the entire plant lifted out of the soil!
Anyone has insight into what is happening to these plants? I'm worried about a soil disease, as I don't see any signs of bugs or mealy worms. These are planted in full sun and I water often to keep my garden beds looking lively...except for these that are dying.