Gardens

How to prune azaleas – and when to leave them alone

Find out when and how to prune azaleas to enjoy the best from these colorful flowering shrubs

how to prune azaleas after they have flowered
(Image credit: Future)

How you prune azaleas can differ depending on the type of plant that you have.

Azaleas are flowering shrubs that are part of the rhododendron family, producing long-lasting flowers in spring that will clothe the bush in a mass of color – with varieties available in all hues, ranging from white to deep crimson. 

They don't mind a bit of shade, so are popular plants for flower bed ideas in darker corners of the garden, or under trees, where they can inject a bit of much-needed color. The best time to plant azaleas is spring or early fall, so they are a good choice of shrub when deciding what to plant in September.

There are, however, two types of azalea, so before you bring out the pruners, you need to be sure of the variety you have planted in your garden.

Azalea

(Image credit: Primrose)

How to prune azaleas of different types

Before pruning azalea bushes, determine which of the two types you have:

  • 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 evergreen, 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 and well tended to, only need pruning either to remove dead wood, or reduce their size if they are starting, fo 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.

Orange azaleas in spring in a garden

(Image credit: Getty Images/ Jacky Parker)

Pruning azaleas step by step

Follow these steps for pruning azaleas:

  • 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.

Azalea George Tabor pink blooms

(Image credit: Getty Images/ Teresa Kopec)

What time of year do you prune azaleas

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

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 rejuvenation pruning below)

Pink azalea blossoms in a shady area of a garden

(Image credit: Getty Images / Cyndi Monaghan)

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.

How hard can you cut back azaleas?

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

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.' 

If an azalea is cut back heavily then it will not flower in the following year, but this will be worth it if an old shrub past its best is then transformed back into a young, healthy and well-shaped azalea in future years.

pink azalea blooms on a large shrub

(Image credit: Getty Images / Keith Getter)

How do you prune overgrown azaleas?

The best way to prune old or overgrown azaleas 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 shoots back to 6 inches to encourage the plant to branch,' say Miracle-Gro.

You can also 'spread the rejuvenation pruning of azaleas out over several seasons,' advise the experts at Wilson Bros Gardens.

This more gradual approach is done over a three-year period.

  • 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.

pink azalea

(Image credit: Getty Images)

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.

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.

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

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Rachel is senior content editor, and writes and commissions gardening content for homesandgardens.com, Homes & Gardens magazine, and its sister titles Period Living Magazine and Country Homes & Interiors. She has written for lifestyle magazines for many years, with a particular focus on gardening, historic houses and arts and crafts, but started out her journalism career in BBC radio, where she enjoyed reporting on and writing programme scripts for all manner of stories. Rachel then moved into regional lifestyle magazines, where the topics she wrote about, and people she interviewed, were as varied and eclectic as they were on radio. Always harboring a passion for homes and gardens, she jumped at the opportunity to work on The English Home and The English Garden magazines for a number of years, before joining the Period Living team, then the wider Homes & Gardens team, specializing in gardens.