Rhododendrons will not work in full sun! In a situation like you described,
crepe myrtle will work very well. They bloom very full like the rhodondendrons
but do well in the sun. Also, they bloom from early summer through the fall
and get just a full with color as the rhodendrons. You will love them! Since
they get tall you can plant flowers in front too. I have lillies, coleus, and
clematis around mine and it looks awsome! Hope this helps.