I bought a rhododendron this spring and planted it in my garden. For
several months it seemed to be doing very well. Recently, I began to notice
that some of the leaves on certain branches were developing brown areas.
Others were wilting. Slowly, the entire branch would just sort of dry out
and die. However, other parts of the plant continued to sprout new leaves
and grow. This process seems to have picked up some steam in the last 2
weeks. More sections are looking unhealthy. I fear it is going to slowly
die. Does anyone have any idea what the problem might be. I water
regularly and fertilized it in the spring with an appropriate fertilizer. I
do believe it may be getting a bit too much sun, but other plants in the
neighborhood with similar sun are doing fine. (I am in NY)

Any help?