The leaves of a normally healthy, mature Rhododendron of approximately 15 years, mysteriously went limp last October. This plant is a hardy seed grown variety which requires low maintenance. And now that the weather is warming up, the leaves are more limp than ever. I am knowledgeable regarding acidity, soil composition, planting depth and location but not so much regarding diseases. I've been online trying to search out the cause(s) to no avail. Is there anyone who might be able to offer an explanation. Puzzled J.