No worries, most plants take a year and many shrubs and trees three or more years to settle in and become mature enough to flower. Your rhododendron looks lovely in the photo so I know you are planting things correctly and watering when needed. Many blooming shrubs only have flowers for a couple of weeks so don't expect long lasting flowers like you find on annual or bedding plants. If another two years go by and these shrubs still have no flowers you can start to worry. Keep growing, Marianne Binetti