Did you water last August? Rhododendrons that have buds but fail to bloom could have suffered from dry weather in August or September so that the flower buds dried up in order to conserve moisture for the rest of the plant. Another reason for rhodie bud blast\" is cold winter weather. Sometimes the wind chill is cold enough to freeze the buds off but not so cold that it damages the foliage. Rhododendrons have very shallow roots and dry out easiy. Try a one inch mulch of bark chips around the base of the plant and let a slow running hose saturate the soil during the dry months of summer. Depending on your zone