Azalea or rhododendron?
A common question in the spring is what's the difference between a rhododendron and an azalea?
- All azaleas are in the genus Rhododendron, which are in the Ericaceae or Heath family, but azaleas belong to different subgenera such as Pentanthera (deciduous azaleas) and Tsustusti (mostly evergreen azaleas).
- All azalea flowers have five lobes while most, but not all rhododendrons, have a larger number. Azaleas usually have one stamen for each lobe, making five stamens. Other rhododendrons have two or more for each lobe, ten or more for each flower.
- Azaleas tend to have hairs that grow parallel to the surface of the leaf (called appressed hairs). Rhododendrons have hair, called indumentum. The hair, when it does exist, may be long, short, thick, thin, matted or upright. Some rhododendrons have scales and are known as Lepidotes. Scales are minute disc-like dots that occur on many parts of the plant. If no scales exist, it is an Elepidote. All azaleas are Elepidotes, bearing no scales.
- Azaleas have tubular-funnel or funnel shaped flowers while other rhododendrons are more varied in the flower shapes and sizes. Besides the above, flower shapes may be saucer, bowl, funnel like, broadly campanulate, tubular, rotate or ventricose (swollen, inflated or distended).
- Deciduous azaleas lose all their leaves in winter, while true rhododendrons are evergreen, and are genetically different enough from the evergreen types that they rarely cross breed.