How to prune an azalea?

Azaleas delight us with their breathtakingly generous spring flowering. Deciduous or evergreen depending on whether they are Chinese or Japanese, they slowly form medium to large bushes, from 60 cm to 2 m in height, with a similar spreading. Chinese Azaleas are scented and offer lovely autumn leaf colour while Japanese Azaleas naturally display a compact, rounded habit all year round. They can be grown in ground or in a pot. Once placed in the right location and in suitable soil, they are easy to care for and require little maintenance. Pruning an azalea is optional; it simply removes dead wood and damaged branches, rejuvenates a specimen and can be used to alter its silhouette.

Pruning azaleas is carried out after flowering, which takes place from March to June depending on species and varieties. It differs according to whether you want to prune an evergreen Japanese Azalea or a deciduous Chinese Azalea and is not carried out for the same reasons.

For everything about growing Azalea, see the article: Azaleas: planting, cultivation, pruning and care.

Spectacular Azaleas and Rhododendrons at Schönbrunn park.

When to prune an Azalea?

All azaleas are pruned once flowering has finished, bearing in mind flowering ranges from March for the earliest varieties to May for the latest. Take care with Azaleas from the "ENCORE" series that reward you with two to three flowerings during the year: practise pruning after the first flowering, without waiting for the second wave of flower buds that appears from May onwards.

How to prune an Azalea?

Required equipment

To prune an Azalea, equip yourself with gloves and a pruning shear. Make sure to disinfect them with alcohol beforehand to avoid transmitting disease from one plant to another.

Pruning the Japanese Azalea

Although Japanese Azaleas have a naturally compact, rounded habit year round, you may wish to refine their shape, perfect their roundness or prune them into a cushion. Note that this pruning is not essential: you choose to prune them to adjust their shape, but you can also let them grow freely; azalea care is simple.

Maintenance pruning

To prune a Japanese azalea correctly, proceed gently, following these steps:

Use a cleaned pruning shear
Remove spent flowers
Remove damaged or sparsely leaved stems
To restore the specimen's rounded shape, locate where the wood is leafless. This is your limit not to reach
Shorten the green shoots with your pruning shear following the plant's shape
Step back regularly to review your work and adjust your cuts accordingly

Japanese practitioners prune Azaleas very regularly and carefully to obtain such regular results; this type of pruning is called "tamamono" (photo t.kunikuni)

Cloud pruning

If you wish to prune a Japanese Azalea into cushions or clouds, work on an already mature specimen and be patient!

In the first year, remove bare or dead branches
Remove vertical branches, then remove short horizontal branches
In the second year, remove fine branches growing under the formed plateaux to clear the lines
Then remove the branches growing above the plateaux to keep only the plateaux at the extremities, which you shape into rounded forms
Proceed in this way for several successive years to densify this form
Thereafter, merely remove poorly placed shoots and balance the overall appearance of the bush

Pruning the Chinese Azalea

The Chinese Azalea is pruned only for two reasons: first to rejuvenate an ageing plant showing too much bare wood or a lanky shape; second to encourage its branching to thicken the specimen.

Use a cleaned pruning shear
Remove spent flowers
Identify points of branching on your specimen
Operate above those points by shortening branches judged too long
Observe the base of the plant
You can prune old branches if you see young branches taking over

How to train a Japanese Azalea on a stem?

Equipment and technique

Required equipment is the same as for other prunings: a simple, well-cleaned pruning shear and gloves.

If you wish to prune a Japanese Azalea into a standard on a stem, proceed as follows:

It will be easier to work on a potted azalea so you can turn it as you go
Choose a central branch to act as trunk
Decide at what height you want to form the crown and mark that point. Generally, to obtain a balanced result, remove the lower third
Remove all shoots arising from the collar up to your mark, as well as suckers below the collar
Install a stake on your trunk with ties that are not too tight
Prune the Azalea's crown to form a head. Be careful not to reach leafless wood. You can choose to form a round, elongated or pyramid-shaped head

Carry out maintenance pruning once a year for the first three years, while the trunk thickens and to keep a balanced appearance. Pinch out new shoots above a leaf to thicken the branches and form your crown.

Finally, note that Azalea can also be trained as a bonsai.