This pruning guide applies to Azalea and Rhododendron as well as all other evergreen shrubs that flower in late winter, spring, or early summer.
The most basic form of pruning requires you to deadhead the old flowers before they can make seed. This is performed by cutting back to the first set of buds.
If you notice any shoots spoiling the overall shape of the shrub, they can be cut back to a suitable position too.
Prune after flowing:
- evergreen Viburnum
- evergreen Berberis
- Brachyglottis (Senecio)
- Evergreen Ceanothus
Prune if necessary;
Don’t hard prune:
- Daphne (minimal)
- Garrya eliptica
- Kalmia latifolia
- Osmanthus (Early flowering species)
When & How to Prune
The timing of Rhododendron and Azalea pruning is important to ensure flowers for the following year. All summertime pruning should take place after flowering in early to late July, as this will give them plenty of time to flower next year.
A popular misconception about these common plants is that they bloom during winter. This isn’t true – it’s just when their buds are forming and opening up before dropping off shortly thereafter.
The new shoots need to be pruned. This is done by deadheading the old flowers before seed starts setting on that shoot, which will then direct all of its energy towards growing more branches and flower buds.
Prune too late though, and there won’t be time left in the season’s growth cycle for your Rhododendrons to produce any blooms – but they may grow another bud like a leaf instead which will bloom next year.
Rejuvenation Pruning for Azaleas & Rhododendrons
The most important thing to remember about Rhododendrons and Azaleas is that they are slow-growing shrubs. This means you need a lot of space for them in the future so make sure not too plant these plants close to any other vegetation or obstructions.
If this happens, you will have to cut back hard when the bushes reach its maximum height.
All large Rhododendrons and Azalea, both deciduous (losing leaves during winter) and evergreen (having green foliage year round) respond well to some hard pruning.
When winter comes to an end, it is a good time of year for trimming back the shrubs. I prefer doing this in early spring – just after all flowers have faded away and before leaves start growing again. The stumps will soon grow new shoots that try to regain their former size as quickly as possible.