There are several reasons for rhododendrons to have few or no flowers:
- Application of nitrogen-rich fertilizer can cause excessive vegetative plant growth and suppression of flower bud formation.
- Plants pruned in the late summer or fall will have few blooms due to removal of flower buds. The proper time to prune is in the spring immediately after flowering has finished.
- Cold weather can kill flower buds. Buds change color from green to brown. Select varieties cold hardy for your garden location.
- Some hybrid rhododendron varieties do not bloom profusely every year.
- Light is the primary factor that stimulates flower bud development. Rhododendrons should be planted where they receive sufficient light so that they set flower buds, but not in too sunny a location that leaf damage occurs.