Plant Study - Azalea vs Rhododendron

Azalea Japonica As you can see from the title, we will be looking at the difference between the Azalea and the Rhododendron, while we wrote about the Azalea in our last blog we will be looking more at the details of the Azalea in this blog. While both plants look extremely similar to each other, they are in fact classed as different plants, read on to find out more about these amazing plants.

First off, there are two main types of Azaleas, you have your Deciduous Azalea and also a Japanese Azalea and also just to keep things complicated, all Azaleas are Rhododendrons but not all Rhododendron are Azaleas. I know this does not make too much sense right now but if you continue reading I promise your question will be answered.

This can be a little confusing for the novice gardener but hopefully this can all be cleared up and you can confidently get these for your garden. Starting off, you can get one of two types of Azalea, either a Deciduous or an Evergreen (sometimes called Japanese) Azalea. Obviously the main difference between the two is that one is evergreen and the other is deciduous (I know, shocking right?). Now, to tell the difference between an Azalea and Rhododendron is a bit trickier. The easiest way to tell is that most Rhododendrons are evergreen so will keep their leaves through winter, with the exception of a few varieties. The Flower shape is another way to tell the difference, the Rhododendron Flower is Bell Shaped, while Azalea are usually Tubular or Funnel shaped.

However the main difference why these plants are classed differently is because the Azalea has 5 Stamens while the Rhododendron has 10 Stamens. Evergreen Azaleas are smaller and grow a little slower while the Deciduous variety grows roughly to 6ft in the right conditions

The Reason behind this is that Botanical taxonomists have put both the Azalea and Rhododendron in the same Genus as I have said earlier there are differences between the plants but not enough to constitute different names!

Now we know the difference between Azaleas and Rhododendrons, we can look at planting them and how best to take care of them. Both Azaleas and Rhododendrons are Lime-hating plants meaning they prefer Acidic soils. We have all had that lesson in science class where we have been told the pH levels are measured on a scale from 14 to 0 where 0 is the most acidic something could be, while 14 is the most alkaline and 7 is totally neutral.

Azaleas enjoy being planted in Acidic soils between 4.5-6.0 pH while rhododendrons prefer 4.5-5.5 pH. This is important to keep in mind while planting as you cannot put it in a bed with a lot of other plants without also making sure that they also tolerate or even prefer Acidic soils.

Home test kits for your soil are easily available at most garden centres, but if you are unsure of the soil conditions you can pick up a bag of Ericaceous compost that will make the soil more acidic and more hospitable for your new Azaleas/Rhododendrons.

Once you have prepared the soil and have made sure it is a nice free-draining soil you just need to make sure you are keeping the plants well watered/fed and these great plants will thrive in your garden.

Hopefully this gives you more of an insight into differences of the Azalea and Rhododendron, however as you can see, whichever plant you choose they will be a great shrub for any garden!