Blueblossom (Ceanothus thyrsiflorus): when and how to prune

Blueblossom (Ceanothus thyrsiflorus): when to prune it?

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Straight after flowering, in late June or early July.

What else to prune in those months? June · July

Blueblossom (Ceanothus thyrsiflorus): how to prune it?

1. Lightly shorten the flowered shoots, by no more than a third of the new growth.
2. Only cut into green, leafy wood.
3. Against a wall, cut back shoots that grow outwards.

How much to cut, and how often?

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

What does it mean for wildlife?

• Pruning in June–July can fall in the nesting season (15 March–15 August). Check carefully for nesting birds first: disturbing an active nest is against the law.
• Blueblossom (Ceanothus thyrsiflorus) 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

• Californian lilac
• Santa Barbara ceanothus (Ceanothus impressus)
• Barberry
• Blackthorn
• Box (buxus)
• Cherry laurel

Plant profile: Blueblossom (Ceanothus thyrsiflorus) · Pruning calendar and basic rules