HI. My friend has an established rhodedendrum. It is unfortunatly in full sun but has been flowering for years. A week ago, i looked at it, and the branches have black on the bark that looks like soot, actually reminds me of fire blight. The leaves on the lower half of the plant, are fine, above are discolored, brown, blackish not much green at all and curled and wilted. Quit a contrast to the healthy ones at the bottom half. Buds, some of them have powdery mildew. They haven't opened as of 4 days ago. The branches do not appear damaged other than the dark sooty look. Wondering if its a disease? Also if she can plant in the same soil an azela? Thank you
It sounds like winter burn. This can happen when the shrub goes in to winter without adequate moisture. The fact that the portion that was probably below the snow is still green reinforces the possibility that the top dried out. You can look at the possibilities on this link but I think it was damaged over the winter. http://www.extension.umn.edu/garden/diagnose/plant/deciduous/azalea/deadbranches.html If it is winter damage, there is no reason why an azalea could not be planted there.