Flame azalea (Rhododendron calendulaceum): when and how to prune

Flame azalea (Rhododendron calendulaceum): when to prune it?

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It needs little pruning. Do it just after flowering, in June, because next year’s flower buds form in summer.

What else to prune in those months? June

Flame azalea (Rhododendron calendulaceum): how to prune it?

1. Snap or cut off spent trusses if you wish.
2. Remove dead, weak and crossing branches at the base.
3. Shorten overlong branches just above a side shoot to adjust the shape.
4. An old, bare shrub can be cut back to 30–50 cm above the ground in March: it usually regrows, but will not flower that year.

How much to cut, and how often?

• One pruning period a year: June.
• Prune in moderation: never remove more than about a third of the shrub at once.

What does it mean for wildlife?

• Pruning in June can fall in the nesting season (15 March–15 August). Check carefully for nesting birds first: disturbing an active nest is against the law.
• Flame azalea (Rhododendron calendulaceum) flowers in May–June, when it attracts bees.
• If pruning falls during flowering, wait until it is over or leave part of the plant to flower, so bees and butterflies still benefit.
• Prunings can go on a dead hedge or brash pile in a corner of the garden: shelter for hedgehogs, wrens and insects.

Common mistakes

• Clipping without first checking for nesting birds.
• Leaving a stub or sawing flush with the trunk: cut just outside the branch collar.

Nearby: related pruning guides

• Rhododendron
• Dwarf rhododendron (Rhododendron impeditum)
• Royal azalea (Rhododendron schlippenbachii)
• Torch azalea (Rhododendron kaempferi)
• Western azalea (Rhododendron occidentale)
• Yakushima rhododendron (Rhododendron degronianum subsp. yakushimanum)

Plant profile: Flame azalea (Rhododendron calendulaceum) · Pruning calendar and basic rules