Rhododendrons only flower once per season. There are a few things that could be preventing yours from flowering. If it is recently planted (within the last 5 years) it may not be well-established enough to flower yet. Plants like rhododendron won’t flower until they have energy to spare…flowering takes a massive amount of energy. To help it get established more quickly I recommend mixing bone meal (phosphorus) into the planting hole. The phosphorus in bone meal stimulates root growth and flower production…both things we want from a new rhododendron. Spring feeding is a must for better flowering (or any flowering in your case). Instead of using an evergreen food like Holly-Tone try Flower-Tone instead. Flower-Tone is a granular food that also will provide phosphorus to help stimulate flowering. To get the Flower-Tone to the roots where it’s needed you should pound holes about 10″ deep in a circle out away from the trunk of the rhodo and full those hole halfway with Flower-Tone. You can use a hammer and pipe to pound the feeding holes. Don’t feed now but in the spring as soon as the ground thaws. Rhododendron make the buts for next year this year so, if there are no buds on your Rhodo now then there will be no flowers in spring. If a Rhodo is planted where there is a lot of drying winter wind (say on the west or north side of the house) they will need a windbreak made of stakes and burlap or, better yet, move then to the east side of the house out of the prevailing winter wind.