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11/02/2014 at 12:59

Apologies, I'm sure there is an easy answer to this, but what is the difference between a rhododendron and an azalea ?  I thought it was if they had small leaves - azalea big leaves then a rhodo, but now completely confused.  Any answers ? 

11/02/2014 at 13:23

Hi peanuts3.

Hope this helps to explain.

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 but here are a few characteristics to look for.

True rhododendrons have 10 or more stamens which is 2 per lobe. Azaleas usually have 5 stamens or 1 per lobe. Azaleas have 5 lobes in a flower.

Azaleas tend to have appressed hairs which is hair parallel to the surface of the leaf. This is particularly true along the midrib on the underside of the leaf. It is easily seen in "evergreen" azaleas. True rhododendrons instead of hair are often scaly or have small dots on the under side of the leaf. Azalea leaves are never dotted with scales and are frequently pubescent.

Many azaleas are deciduous. True rhodi's are usually evergreen with the exceptions of R. mucronulatum and R. dauricum.

Azaleas have tubular funnel or funnel shaped flowers. Rhodi flowers tend to be bell-shaped.

Note: This information was obtained from:

Dirr, Michael A. 1998. Manual of Woody Landscape Plants. 5th edition. Champaigh, Ilinois: Stipes Publishing.

Greer, Harold. 1996. Greer's Guidebook To Available Rhododendrons. 3rd. edition. Eugene, Oregon: Offshoot Publications.

11/02/2014 at 15:18

...very interesting Edd and thank you for that.... what I find is that people are still using the old nomenclature, including Garden Centre's... I don't often see the Azalea referred to as Rhododendron.... I grow several of both and there's no way I'm going to call my Azalea 'Mother's Day'... Rhododendron 'Muder Dag'... either... me, Azalea's have a distinct enough shape and growth habit, for me to continue to separate them out... we don't always have to go by what officialdom would like us to....

11/02/2014 at 17:29

I never knew that either but often wondered!

11/02/2014 at 18:08

Thanks Edd - that is really helpful 

11/02/2014 at 22:12

To be honest a azaleas is a azaleas just like Salino Says. Its a visual thing and you get to know what it looks like, there is no need to have to understand the botany stuff like i do, but it is nice to know, for future reference. 

I bet you will forget it in the morning, just like me, that is why i keep notes. My memory is vast for stupid info like quiz questions but lacks the indexing for the important stuff, unfortunately. That is why i write it down. ( only use a computer for quick ref (when it is working) as they tend to brake down and the electric goes off, now and again. Then where would you be?

11/02/2014 at 22:30


Also as a visual.  The leaves are entirely different, in shape, texture and whether evergreen or desiduous, upto a point.

Howevr, whatever.  Both are very beautiful flowers.

11/02/2014 at 23:17

I have to agree Mike but i still like them in their natural habitat rather than my garden. I do have azalea in pots but they never last more than two years with me. 

When i say natural habitat, I meen the lake district and that is personal to me. Its the first place that springs to mind when the words are mentioned. Please do not judge me on that one image as it is a beautiful picture in my head and one i will always come back to.

12/02/2014 at 19:38

Edd.  Believe me.  I never set myself up so as to judge another.   I totally agree with you.  Seeing plants, shrubs etc in a more natural surrounding than what e might attempt to mimmik in our gardens, is so much more delightful and rewarding.  I have always had a desire to visit countries from where many of our plants originate from.


Keep enjoying the wonders and beauties of nature.

12/02/2014 at 19:44

Mike, do you remember the tv programme Geoffrey Smith's World of Flowers where he took us all over the world to find the origins of our garden plants - he was such an interesting man. 

12/02/2014 at 23:09

I quote from the Readers Digest Encyclopedia of Gardening.

Rhododendron. A genus of at least 500 species of greenhouse and hardy trees and shrubs. It includes Azaleas, formerly treated as a separate genus. These differ from other rhododendrons in the following way.

Deciduous azaleas are the only deciduous rhododendrons that do not have scaly leaves.. Evergreen azaleas are not true evergreens; the leaves that are formed in the spring on the lower parts of the shoots fall in autumn.

There are so many pages I have no intention of typing them all out. Browse ebay for the book. I refer to it more than I do to upto date editions of RHS Publications.

Hope this helps.

13/02/2014 at 17:09

Mmm could be entirely wrong - but thought Rhododendrons and Azaleas had been reclassified by the powers-that-be in the world of horticulture and now appear under the Rhododendron umbrella.  Hope I am not talking complete nonsense here, all clarifications welcomed

By the way, talking of such things, I wonder if anyone has been to the Himalayan Garden, Grewelthorpe, Masham, N. Yorks.  A small garden in progress with lakes only open to the public for about 6 weeks in spring, difficult to get the timing for blooms right but well worth a visit if in the area. 


13/02/2014 at 22:45



Yes, I remember.  Over the years there have been severaltv gardeners who obviously were able to provide us with so much, without always having to have a scriptwriter.


I would love to see some of those programs again.

13/02/2014 at 22:47

Sunnylou.  You are absolutely correct.  The powers that be do tend to complicate matters, more often than not.

Not only subjects as rhodo's but also so many everyday perenials as well.

15/02/2014 at 12:13

Hi Mike, your clarification on Rhododendrons/Azales was most useful, thanks

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