I noticed two of my rhododendrons are wilting and appear to be dying! They are about 12 years old and very large. We had a lot of snow this winter and so far a lot of rain this spring. The drainage is not great, but they have done well in their spots for so long. I don't see any bugs and have started to be concerned about root rot or weevils. Should I cut them back and hope for the best or move them? At least half of each plant appears ok and there are numerous flower buds on them. I would hate to lose them after so many years.