Photo: Wouter Hagens, Public domain · source
Pruning guide · Shrub
Pieris: when and how to prune
Pieris japonica
Prune a pieris after flowering, in May: cut off the faded flower clusters just below the cluster, and shorten overlong or crooked branches to just above a whorl of leaves.
Pieris, or lily-of-the-valley shrub, is an evergreen shrub for acid, humus-rich soil in partial shade, with clusters of white or pink bells in spring followed by fiery red young shoots. The flower buds for next spring are ready all winter. That is why you prune it straight after flowering, and then not again. It needs little pruning. Wear gloves: all parts are poisonous, including the flowers.
| Pruning months | May |
|---|---|
| Nesting season (15 March–15 August) | Take care in May |
| Flowering | March–April |
| Good for bees, butterflies and birds | Yes, for bees |
| Native to Belgium | No, planted |
| Poisonous to people and pets | Yes, take care with children and pets |
Pieris: when to prune it?
Prune after flowering, in May, when the last bells have faded.
Don’t prune later in summer: it is already forming the flower buds for next spring.
Cut off young shoots killed by a late frost as soon as you can see what is dead.
What else to prune in those months? May
Pieris: how to prune it?
- Cut off the faded flower clusters just below the cluster, without damaging the leaves below.
- Shorten overlong or crooked branches to just above a whorl of leaves: it will sprout again there.
- Remove dead twigs and twigs killed by frost.
- Rejuvenate an old, bare shrub over two or three years: each time after flowering, cut part of the oldest branches back hard.
- Never throw the prunings into a field or pen: goats, sheep, horses, rabbits and guinea pigs are very sensitive to them.
How much to cut, and how often?
- Little: every year the faded flower clusters, and now and then a branch that grows out of shape.
- An old shrub: spread over a few years, never everything at once.
What does it mean for wildlife?
- May falls in the nesting season (15 March–15 August). Blackbirds sometimes nest in a dense, evergreen pieris: look carefully first, and spare an active nest.
- The bells in March–April are an early meal for bumblebee queens, which push their long tongues into the flowers.
- For most other native insects a pieris is of little value. Combine it with native plants for acid soil, such as bilberry, heather or rowan.
- Birds and hedgehogs eat the vine weevil grubs that feed on the roots. Leave some leaf litter under the shrub.
Common mistakes
- Pruning later in summer, so the flower buds for next spring are lost.
- Damaging the new shoots below when cutting off the clusters.
- Throwing the prunings into a field or an animal pen.
- Cutting an old shrub back hard in one go.
Caution: Only on acid soil; water with rainwater. Pieris is poisonous: wear gloves and keep clippings away from children, pets and livestock.
Nearby: related pruning guides
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