I have three rhododendrons. Two have small blooms and the other has large blooms. The two smalls bloom well every year. Last year and this year the one with the large blooms hasn’t bloomed at all. The plant seems healthy enough and has lots of buds on it but they don’t actually flower. What could be the problem?
"It's not unusual for newly planted rhododendrons to spend their first few years in the garden becoming established in place of setting flower buds and blooming. It doesn't mean anything is wrong, they just need time.
"Shade is probably the most frequent cause of failure to bloom with established plants. Sunlight, or at least light, is required to set flower buds.
Over fertilization with high nitrotgen fertilizers will produce vegetative growth in place of flower buds. Rhododendrons have low nutritional requirements compared to most other shrubs. Overfertilized plants will also be more susceptible to winter kill of both foliage and flower buds."