There is a wilting, pale section in my huge bank of reliably blooming azaleas. Also, please see the photo of some other developing issues. I have not pruned or fertilized them yet.
Is this more rain damage? Is there an all-purpose solution?
This appears to be root rot. The roots of an azalea absorb the water the shrub needs and the minerals the shrub needs.
When a section of the roots gets sick and does not properly absorb mineral nutrients from the soil, the section of the shrub nourished by those roots turns yellow and chlorotic.
When the roots are killed and stop functioning, the section of the upper part of the shrub connected to those roots is deprived of water and suddenly wilts and dies.
It is virtually impossible to properly treat root systems growing in the ground, so there are no practical treatments for this problem. The frequent and large amount of rain this spring/early summer is the main issue. The water molds that cause most root rot problems, like Phytophthora, are far more likely to attack roots when extended periods of wet soil occur.
Prune out the dead areas back to living tissue. The azaleas may survive this and recover if the weather will turn drier.
Consumer Horticulture Specialist
The LSU AgCenter and the LSU College of Agriculture