Azaleas are Rhododendrons
A Common Question
By Harold E. Greer
flammeum 'Hazel Hamilton'
Picture by S & J Perkins
What is the difference between a rhododendron and an azalea?
- All azaleas are rhododendrons. They belong to the subgenus
Pentanthera (deciduous) and the subgenus Tsutsusi
(mostly evergreen) by the revised classification or to the Azalea
Series by the Balfourian System.
- All azaleas are elepidotes (they never have scales).
- All azaleas have five lobes to the flower.
- Most (not all) azaleas have only one stamen for each lobe of
the flower, meaning they have five stamens while most other
rhododendrons have two stamens for each lobe, meaning they have 10
or more stamens.
- Azaleas tend to have adpressed hairs (hair that grows parallel
to the surface of the leaf). This is particularly true along the
midrib of the undersurface of the leaf and is easily seen in the so
called "evergreen" azaleas.
- Azaleas have tubular funnel or funnel shaped flowers.
- You would need a microscope to see this, but while the hair on
"standard" rhododendrons will often branch, the hair on azaleas
[This article is from Greer's Guidebook to Available
Rhododendrons Species & Hybrids which is an excellent
reference for anyone interested in learning more about the genus
Notice the rhododendron pictured above has a flower consisting
of five lobes and five stamens so it is commonly referred to as an
azalea. Rhododendron canadense is an
example of an azalea that has 10 stamens.