My neighbour has a Rhododendron in a tub (north-east facing). It is covered in buds which are not opening and the leaves are wilting. Anyone know what's wrong?
http://pep.wsu.edu/hortsense/ Click on Ornamentals then Rhododendron for things that affect them along with pictures.
They can suffer from fungal diseases such as Botrytis shoot blight which sounds possible.
They do of course require acid conditions and their leaves will yellow if it gets too alkaline. If it's a hard water area you might be advised to water with rain water or to give them some ericaceous fertilser from time to time
Thank you jake-the peg, i've had a look at the site you recommended and the pictures suggest the problem may be Phytophthora root rot. I will pass the information on.Thanks again, Paul.