I have 5 rhododendroms and last summer the middle one died. I thought the heat affected it so it would come back, but it didn't. There are two leaves on the bush, and the expert on WDEL thought it was a ground disease and I should send you a small branch and the live (few) leaves. Suggestions? Also, do you have hours so perhaps I can drop this off? Thank you. Joe Vattilana
Having one rhododendron die in the line of five does make me think that there may be a root or soil drainage issue. When were they planted, are they established shrubs? If newly planted, you may have a guarantee from the garden center or nursery. It may also come back out if you prune it back. I would be glad to look at a sample, but the best sample would be a small branch and a few roots. If you can use a trowel and cut off a few roots and place them in a closable plastic bag, that would be great. Rhododendrons prefer well drained soil, and are susceptible to some root rot causing fungi.
Here is the web site where you can download the sample submission form and instructions: http://extension.udel.edu/ag/plant-diseases/ud-plant-diagnostic-clinic/
Thank you for contacting Cooperative Extension,