Azaleas and rhododendrons look so much alike that it’s easy to assume they’re the exact same plant with two different names. But is that really the whole story, or are there some subtle, key differences you should know about before heading to the garden center?
Is there actually a difference between Azaleas and Rhododendrons?
Back in the day, azaleas and rhododendrons were classified as two completely separate groups. Fast forward to today, and they both officially belong to the *Rhododendron* genus. In the gardening world, we still use the name “azalea” for deciduous varieties and certain small-leaved evergreens. The biggest takeaway? While some azaleas love living indoors, true rhododendrons are strictly outdoor plants!
The botanical backstory
If we’re looking at pure botany, there used to be a very clear line in the sand. The famous botanist Carl Linnaeus originally categorized azaleas as their own genus because they only have five stamens. There was also an old rule of thumb that any deciduous rhododendron was automatically an azalea. Nowadays, the science has caught up, and they are all officially part of the big *Rhododendron* family.
Which plants do we call “Azaleas” today?
The term “azalea” isn’t really a scientific classification anymore; it’s more of a traditional nickname used by gardeners and nurseries. It generally covers deciduous rhododendrons and certain small-leaved evergreen species. Here are a few popular examples:
- Rhododendron luteum (Pontic Azalea)
- Rhododendron japonicum (Japanese Azalea)
- Rhododendron molle (Mollis Azalea)
- Rhododendron quinquefolium (Five-leaf Azalea)
- Rhododendron simsii (Indian Azalea)
Spotting the differences: Azalea vs. Rhododendron
The most obvious giveaway is that almost all rhododendrons keep their leaves year-round (evergreen), while many azaleas drop theirs in the fall (deciduous). Rhododendrons are rugged outdoor shrubs, whereas certain azaleas are perfectly happy as houseplants. Here are a few other ways to tell them apart:
- Azaleas can usually handle a bit more sun than rhododendrons (check out the best spots here).
- Azaleas tend to stay smaller and more compact.
- Azaleas generally have smaller, daintier leaves.
Do they share any similarities?
Absolutely! Both plants are “acid-lovers,” meaning they need very acidic soil with a pH between 4 and 5 to thrive. Their general care routines are also quite similar. The main outlier is the Indian Azalea—since it isn’t frost-hardy, it has specific needs when it comes to overwintering. If you’re looking at bloom times, outdoor azaleas usually start flowering about two months later than rhododendrons and finish up a bit earlier, though their seasons do overlap for a good two months.
Pro Tip: Check for hardiness before you buy!
While evergreen rhododendrons are typically very cold-hardy, azaleas can be a mixed bag. Because the names are sometimes used interchangeably at shops, always double-check the hardiness zone on the tag before planting one in your backyard. You want to make sure your new leafy friend can handle your local winter!