How to prune azaleas – to keep them healthy and beautiful

Learning how to prune azaleas is easy and worthwhile. You will be rewarded with healthy plants that continue to bring color to your garden. 

Azaleas are popular flowering shrubs in the rhododendron family. They are prized for their wide range of hues, including warm oranges and cool and tranquil pale pinks. 

It is easy to grow azaleas and to take care of them, making them a very popular choice for gardeners. They can be prone to some azalea diseases though, so knowing when to plant azaleas and regular pruning is a great way to ensure that your plant stays healthy. 

When learning how to prune azaleas, you must first consider that there are two different types. It is therefore important to ascertain which type you have, so that you get the pruning correct. 

It is just as important to know when to leave azaleas alone and not prune. Taking the time to acquaint yourself with the practices using this simple guide will keep your azaleas beautiful year after year and a worthy addition to your flower bed ideas. 

How to prune azaleas of different types

Azaleas have large showy flowers that cover the plant in spring. They are tolerant of some shade and add a huge burst of color in spring to any border, so are a good choice as shrubs for shade. 

Before you can know how to prune azaleas, determine which of the two types of these flowering shrubs you have. Although they are part of the same family, there are differences from how to prune rhododendron:

• Evergreen azaleas – also known as Japanese azaleas – tend to be smaller, growing to about 18-30 inches (40-80cm) and include dwarf azaleas. Evergreen azaleas are mostly native to Asia.
• Deciduous azaleas are taller, losing their leaves in the fall, with some first changing color from golden through to flaming red and brown before they drift to the ground. Most native to North America are deciduous species.

Once you have determined whether your plant is deciduous or an evergreen shrub, you can then focus on how to prune azaleas.

Deciduous azaleas only need to be lightly pruned to remove diseased or damaged stems.

Evergreen azaleas, so long as they are placed in the correct position with the right soil type, and are well tended to according to the conditions in your hardiness zone, only need pruning either to remove dead wood, or reduce their size if they are starting, for example, to grow over a pathway.

'The first rule of pruning evergreen azaleas is to select the right varieties in the first place and plant them where they will do what you want without a lot of pruning,' is the advice from The American Rhododendron Society.

Pruning azaleas step by step

Azaleas have been popular since the days of Victorian garden design – and it's easy to see why with their beautiful blooms. Follow these steps for pruning azaleas t keep them looking their best:

• Using sharp pruning spears or hand pruners, cut individual branches.
• Cut back any branches that have outgrown the shape of the plant you are looking to create.
• Cut the branches off to a natural spot so that they will regrow in a nice shape.
• Remove dead, damaged or crossing shoots – damaged branches beyond the point of break and above a leaf, and dead branches at their origin.

'When pruning back, try to leave some leaves on the shoot, as you will get better branching from the buds near the leaves,' advise the experts at rhododendron and azalea specialists Millais Nurseries.

How and when should azaleas be pruned?

How and when you should prune azaleas will depend on the type that you have, and its condition. Using this guide, you can identify the type of azalea that you have and apply the correct pruning regime. 

You should lightly 'prune evergreen azaleas immediately after the blooms have faded in spring', advise the experts ay Wilson Bros Gardens.

Azaleas can be lightly pruned after flowering to remove any diseased material.

You should not prune evergreen azaleas at the end of summer or in fall, 'because you want to avoid cutting off fall-produced flower buds that will be next spring's blooms,' they continue.

Pruning azaleas should therefore stop by mid-summer. Heavy pruning of azaleas should be done in late winter and early spring – see tips on rejuvenation pruning below.

How often should you trim azaleas?

'Regular light pruning of azaleas after flowering can dramatically improve the habit of a misshapen azalea plant over the course of a few seasons,' advise the experts at Millais Nurseries.

It may also be necessary to control azaleas which are taking up too much space next to a drive or a path, especially if they have been included as shrubs for the front of the house.

How far back can you trim an azalea?

How far back you can trim an azalea will depend on how large and old it is.

A plant that is in good condition may require little or no pruning. If you want your plant to grow large, especially if it is a shrub for privacy, avoid pruning it too much, and just stay on top of any diseased-looking material. 

If it is a scraggly azalea or has grown out of control, 'sometimes radical action and heavy pruning is required,' says the experts at Millais Nurseries. 'But there are no half measures and it will open up a large hole in the landscape.' 

A plant that has grown too large, particularly if you're trying to develop a bonsai tree type, or is starting to look unkempt, can be pruned back hard to re-establish its shape and to keep it under control. But bear in mind it may not flower the following year. This will be worth it, though, if an old shrub past its best is then transformed back into a young, healthy and well-shaped azalea in future years. So don’t be afraid to take drastic action when required.

How do you prune azaleas to rejuvenate?

How to prune azaleas to rejuvenate them if they are overgrown or old is to give them a new lease of life with a harsh trim.

Rejuvenation pruning azaleas should be done in 'late winter or early spring,' explain the experts at Miracle-Gro. 'You'll have a year without flowers when you do this,' they add.

• Cut the branches back to about 12 inches above the ground.
• 'Once the plants have started to regrow, prune the end of any strong growing new upright shoots back to 6 inches to encourage the plant to branch,' say Miracle-Gro. This will create a thick, attractive plant. 

You can also 'spread the rejuvenation pruning of azaleas out over several seasons,' advise the experts at Wilson Bros Gardens, pruning some of the plant each year. This will maintain some of the blooms and will feel less daunting.

This more gradual approach is done over a three-year period, as follows:

• Cut about 1/3 of the largest scraggly azalea branches to within 6 to12 inches of the ground in early spring.
• Repeat for another two years.
• By the end of the three years all of the old wood will be removed and the azalea will have healthy new growth.

Can azaleas be pruned back hard?

You can prune azaleas back hard, but it may affect their ability to produce flowers the following year. This course of action might be necessary, however, to stop one from taking over your bed or border, and stop it crowding or shadowing other plants. 

How hard you cut an azalea back will depend on how large and how old it is. Larger, older azaleas can be cut back harder than smaller plants.  

Will azaleas grow back if cut down?

Azaleas will grow back if cut down with the method used for rejuvenation pruning, as above. You need to make sure that you do this at the correct time of year, in late winter or early spring, before the growing season, so that the plant will produce new growth.

Azaleas are fairly fast growing shrubs, and the plant should have grown to a nice shape and produce lots of beautiful blooms within about three years after this manner of extreme pruning.

This feature was created by H&G sister brand, Period Living magazine

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