Our site is reader supported, this means we may earn a small commission when you buy through links on our site.
Growing Rhododendrons and Azaleas In Pots
Last Updated on January 21, 2020 by John
There are hundreds upon hundreds of rhododendrons and azaleas from which to choose and you have likely seen some dwarf rhododendrons at your local nursery and garden centre. These dwarf varieties can be effectively grown in pots. Because rhododendrons are shallow-rooted even some of the larger varieties will grow well in pots too. So, whether you have a limited amount of space in your garden or you just want to showcase the rhododendron as a focal point, container growing is a wonderful way to include your favourite plants and that evergreen appeal. But in order to grow rhododendrons in pots, you have to make sure that you pick the right type of plant, the right pot, integrate the most appropriate well-drained compost, and care to it long term.
Choosing the right variety – ideally a dwarf variety
If you are going to grow a rhododendron in a pot, you should try and find a dwarf variety ideally. If you get a variety that is smaller, dwarf variety, you won’t have to contend with a great deal of pruning or shaping down the line. Moreover, you won’t have to worry about choosing a very large container as the larger varieties obviously need a larger pot. Instead, you can simply buy a smaller variety and a regular-sized pot. Some of the most popular dwarf varieties include the Rhododendron yakushimanum cultivars, the Ostbo’s Red Elizabeth, and Rhododendron Lutescens which is a deciduous variety.
Choosing a pot
When you go about choosing a pot for your rhododendrons you have to take into consideration the size of rhododendron will become, not the size it is now. The size of your plant in the size of your container should be the same. Essentially, if you buy your Rhododendron from a garden centre or a nursery you want to select a pot that is approximately one-third larger than the container in which the Rhododendron arrived, you don’t want to go to large, there best potted into larger pots gradually at first every few years.
In addition to size you need to be cognizant of drainage. While most containers if not all containers do come with some drainage holes built into the bottom, these are typically insufficient for plants that need extra drainage like the rhododendron that is prone to root rot. To that end, depending on the material that you choose for the container you can always add additional drainage holes at the bottom. If you have a plastic container for example and you see that the bottom has four holes about the size of a tiny button you might consider drilling more holes around the perimeter. The top reason rhododendrons fail when grown in containers or pots is simply because of poor drainage. Don’t forget to add plenty of crockery to the bottom of the pot so the holes don’t get blocked.
TOP TIP – Rhododendrons root structure is also shallow so they prefer wider, shallow containers rather than tall narrow containers.
Best compost for rhododendrons
Rhododendrons should be grown in a container with a potting mix design for Rhododendrons, azaleas or other acid-loving plants. This type of potting mix has a high level of acidity to it. Rhododendrons need compost that is rich in acidity. In fact, many gardeners who have heavily alkaline soil in their garden can still grow a rhododendron in a container specifically. This type of plant is not something you can grow in alkaline soil just by amending the soil here and there. It’s simply won’t work. To that end, container growing with a highly acidic compost in a wonderful solution for those who find themselves in this predicament. With this in mind, you will need ericaceous compost which is perfect for rhododendrons.
Watering and feeding
Rhododendrons need a lot of water and prefer moist soil but they don’t like wet soil which is why it must be well-draining. They aren’t grown in areas that are wet like a swamp or the edge of a lake but they do best if they get access to ample rainwater as their main source of watering. Even in containers, this is true so if you have to supplement for a few months during the summer, you might notice the leaves turning yellow which is indicative of hard water. This is usually what happens if you use tap water and you live in a hard water area. If you can, it’s recommended that you collect rainwater and then use that to supplement any watering needs.
The plants should be placed anywhere they get partcial shade or dappled shade. They need access to Sun but you don’t want too much sunlight as this can scorch the foliage and the flowers. Given that they are acid-loving it’s important to apply a fertiliser every spring specially designed for acid-loving plants, sometimes its referred to as ericaceous fertiliser.
Rhododendrons don’t need a lot of pruning. The most you should be doing is removing any dead or diseased parts of the bush you see as soon as you see them and deadheading the spent flowers once they reach maturity. If you need to restrict the size of your container rhododendron you can prune it for that purpose. Rhododendrons will respond to hard cutting back but this is usually not something you have to do with a container plant.
If you have enjoyed your rhododendron this season and you want to enjoy more of it you can propagate from cuttings or seed propagation. Cutting should be done with growth from the current year at the end of summer or autumn. You can also propagate by seed in January.