sudden dieback: what could cause it?
I moved into a new house a month ago, with three seemingly healthy and well-established rhododendrons in the garden. Suddenly they seem to be dying back. The one in the photo, which is the worst, looked fine less than a week ago.
I would really appreciate any advice you might have, because I don't know what to make of it.
The dieback is on multiple branches, and I don't see any evidence of pests. There is a shallow layer of bark mulch, but it's not right up against the plants. There is also a flowering dogwood in this garden, and it has what I would guess is powdery mildew, but now I wonder if the two issues could be related.