Rhododendron 39blue danube39 is a spectacular spring flowering shrub that is suitable for medium to large gardens and woodland settings in late spring exquisite lilac45blue flowers bloomand last until early summer rhododendron is ancient greek for 39rose tree39 and when it is full of flowers it is easy to understand why it does best in full sun or partial sun and planted in humus rich acidic soil this award winning evergreen azalea has an award of garden merit from the rh