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Pruning guide · Tree
Black walnut: when and how to prune
Juglans nigra
Black walnut is best pruned in July–August.
| Pruning months | July–August |
|---|---|
| Nesting season (15 March–15 August) | Take care in July–August |
| Flowering | May |
| Native to Belgium | No, planted |
Black walnut: when to prune it?
In summer or early autumn (July–August), when the tree is in leaf. Do not prune it in winter or spring.
Black walnut: how to prune it?
- Young tree: choose one straight leader and remove competing tops.
- Take out dead, damaged and crossing branches.
- Raise the crown gradually by removing the lowest branches year by year if you want a tall trunk.
- Keep cuts small; leave large jobs to a tree surgeon.
How much to cut, and how often?
- One pruning period a year: July–August.
- Never remove more than about a quarter of the crown at once. Better a little every year.
What does it mean for wildlife?
- Pruning in July–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.
- 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.
Caution: Do not prune in winter or spring: the tree bleeds heavily. Leave pruning of large trees to a professional.
Nearby: related pruning guides
Plant profile: Black walnut · Pruning calendar and basic rules
This guide is compiled from the Bladwijzer plant profile and pruning calendar.