That sounds like a good spot then. Have you tried fertilizing? A couple of years ago, I started fertilizing my rodies both
spring and fall with Holly-Tone with tremendous results. My
plants are literally covered with blooms and they are so healthy that I don't even have to pick off the spent blossoms any more. Without removing spent blooms, rhododendrons can turn into alternate year bloomers.
Also,
plants sometimes need a few years to make good root growth before flowering. Fertilizing will hurry this along.