Difference between Rhododendrons and Azaleas
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Gardeners Know the Dirt: Difference between Rhododendrons and Azaleas
Rhododendron and Azaleas are very closely related. In fact, azaleas are actually part the rhododendron genus. This means all azaleas are technically rhododendrons, but not all rhododendrons are azaleas.
However, let’s first start with the basics. Both are classified as shrubs ― woody perennials that usually have numerous stems growing from its crown and generally smaller than a tree.
| Common Name | Size & Habit | Site Requirements | Uses |
| Azaleas | Variable in height, spread, and habit depending on species and cultivar | Full sun to partial shade; moist, well-drained soil high in organic matter | Shady borders, specimen, naturalizing; many flower colors |
| Rhododendron (Catawba) | 6 – 10” tall and wide; irregularly shaped, heavy, evergreen shrub | Full sun to partial shade; moist, well-drained soil high in organic matter | Shady borders, specimen, naturalizing; many flower colors |
Rhododendron (Catawba)
The Main Differences
Both members of the same family of plants (Ericaceae) and are closely related. However, there are some distinguishing features that can help you tell the difference between the two:
- Flowering time: Both plants have showy flowers that bloom in the spring, but the flowers of rhododendrons are generally larger and more bell-shaped, while the flowers of azaleas are smaller and more funnel-shaped. Rhododendron flowers are also usually borne in clusters, while azalea flowers are borne singly or in small clusters.
- Flower clusters: Rhododendron flowers grow in large, tight clusters at the ends of branches, while azalea flowers are usually borne in smaller clusters along the branches.
- Petal structure: Rhododendron flowers typically have five or more petals, while azaleas have only five. Additionally, the petals of rhododendron flowers are often more rounded and open than those of azalea flowers.
- Leaf shape: Above all, Rhododendrons have large, leathery leaves that are often oblong or elliptical in shape. In other words, azalea leaves are smaller and narrower and tend to be pointed at the tips.
- Growth habit: Rhododendrons are typically larger and more tree-like than azaleas, with a more upright growth habit. In addition, azaleas are often more shrub-like, with a spreading growth habit.
- Habitat: Rhododendrons are more likely to be found in cooler, more mountainous regions, while azaleas are more common in warmer, coastal areas.
Azalea Flowers
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It’s worth noting that some plants are actually a hybrid of these two species, so it can sometimes be difficult to tell the difference.
Finally, by considering these differences in flowering time, leaf shape, growth habit, flower clusters, and petal structure, you should be able to differentiate between the plants with greater accuracy.
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