sudden whole plant wilt
In the past week we have had 3 plants suddenly wilt and while the butterfly bush bounced back some now, the black beauty elderberry died quickly, and the cardinal plant is just wilting now so I don't yet know the outcome. The plants are quite a distance apart, one on each side of the house actually with other closer plants. Using a magnifying glass, the bottoms of the leaves show a little white stuff and a few black spots. The butterfly bush that is recovering some still shows the stuff on the bottom of the still yellow leaves, but the new growth that started at the ends of the branches doesn't and that growth is green and healthy.
Got any thoughts what may be happening that is causing this? I do plan to contact the extension agent tomorrow before we lose more plants.