Click below to listen to my 2 min. Garden Bite radio show/podcast: Rhododendrons vs Azaleas
Are rhododenrons the same as azaleas? Kinda. From the American Rhododendron Society comes this: All azaleas are rhododendrons but not all rhododendrons are azaleas. Azaleas have been reclassified and are now in the genus Rhododendron. There are no clear cut lines for distinguishing all azaleas from all rhododendrons WHAT? Check out this past Garden Bite on Rhodos & Azaleas for the North.
Very generally, Azaleas tend to be smaller with more pointed, narrow leaves that can be fuzzy. They are mostly deciduous, meaning their leaves drop in the fall.
Rhodos are larger shrubs with some cultivars that can grow as large as 20 ft, according to Birds and Blooms. They are evergreen shrubs, they keep their leaves all winter. The flowers of Rhodos grow grouped together at the end of the branches while azalea flowers grow all the stems.
While both of these shrubs prefer a more acidic soil, azaleas like to grow in sunlight while rhododendrons prefer morning sun and afternoon shade.
If you are considering planting either of these shrubs, get a soil test and find out your pH. Generally, Minnesota has neutral pH of about 7 while rhodos and azaleas prefer 4 to 5.5; both like well draining soil.
The University of Minnesota developed the Northern Lights series of Azaleas. There are some really beautiful options from white to orange, yellows to pinks. While they are rated to zone 4, you might consider giving them winter protection anyway.
PJM Rhododendron is recommended for colder climates as is Haaga, a Finnish rhodo that’s hardy to zone 4a.
More on how to tell the difference between these rhododendrons and azaleas.