Northern white cedar: when and how to prune

Northern white cedar: when to prune it?

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Trim a hedge in May–June and late August, no later than mid-September so the new growth can harden off. Check first that no birds are nesting.

What else to prune in those months? May · June · August · September

Northern white cedar: how to prune it?

1. Only cut into the green part: bare, brown patches will not fill in again.
2. Keep the hedge slightly narrower at the top than at the bottom, so the base gets light and stays green.
3. Narrow columns such as ‘Smaragd’ hardly need clipping: just trim any shoots that stick out.

How much to cut, and how often?

• Trim a hedge once or twice a year, after the first flush of growth (late June) and, if needed, in late summer. Check first that no birds are nesting.
• Most conifers do not regrow from old, bare wood. So never cut back into the brown part (exception: yew).

What does it mean for wildlife?

• Pruning in May–June and August can fall in the nesting season (15 March–15 August). Check carefully for nesting birds first: disturbing an active nest is against the law.
• A dense hedge gives birds a place to nest and shelter, and hedgehogs take cover underneath. Leave some leaves at the base.
• 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.
• Cutting back into bare brown wood: it will not regrow from there.
• Letting the hedge grow wider at the top than at the bottom: the base then goes bare.

Nearby: related pruning guides

• Thuja
• Western red cedar
• Leyland cypress
• Lawson cypress
• Beech
• Field maple

Similar to: Difference from Lawson cypress · Difference from western red cedar

Plant profile: Northern white cedar · Pruning calendar and basic rules