Magnolia: when and how to prune

Magnolia: when to prune it?

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Prune after flowering, in May–July, once the leaves are fully grown. The tree is then in full growth and wounds close faster.

Ideally work in May–June, and in July at the latest: next year’s furry flower buds are forming then, and whatever you cut off later won’t flower.

Don’t prune in winter or early spring: you would cut off the flower buds, which are ready all winter, and the wounds bleed.

What else to prune in those months? May · June · July

Magnolia: how to prune it?

1. Use sharp secateurs for twigs and a pruning saw for branches. Saw just outside the branch collar, the swollen ring at the base of the branch, and don’t leave a stub: a stub dies off and lets rot in.
2. Saw a heavy branch in three cuts: first a notch on the underside, then the branch itself a little further out, and only then the stub. That way the bark doesn’t tear.
3. Only remove dead, diseased, crossing and awkward branches, for example a branch growing over the path or against the house. Don’t shorten branches; saw back to a side branch or the trunk.
4. On a grafted magnolia, cut off wild shoots from below the graft as soon as you see them: they have different leaves and grow more strongly.
5. Remove water shoots, the straight, fast shoots that follow earlier pruning, while they are still young, except a few if you want to fill a gap in the crown.
6. Don’t dig or hoe under the crown: the fleshy roots are shallow. After pruning, spread a layer of leaf mould or compost instead.

How much to cut, and how often?

• Ideally not at all: a magnolia with enough room only needs pruning to remove dead or troublesome branches.
• If it has to be reduced, spread the work over several years, with no more than one or two large branches each time. Never remove more than a fifth of the crown in a year.
• Plant a magnolia where it has room to reach its full size, or choose a small species such as star magnolia: you then won’t need to prune to keep it small.

What does it mean for wildlife?

• Magnolias are among the oldest flowering plants: their large flowers were pollinated by beetles before bees even existed. Today bumblebees and honeybees also collect pollen from them in spring.
• Pruning in May–July falls in the nesting season (15 March–15 August). Blackbirds, chaffinches or woodpigeons sometimes nest in a broad magnolia: look carefully into the crown first, as disturbing an active nest is against the law.
• In late summer the cone-shaped fruits open and the red seeds dangle out on threads: a snack for blackbirds and other birds. Leave them on.
• Brush scale insects off the twigs; ladybirds and parasitic wasps will do the rest. Healthy prunings can go on a dead hedge, shelter for hedgehogs and insects.

Common mistakes

• Pruning in winter or early spring, so the flower buds are gone and the wounds bleed.
• Shortening branches halfway or cutting the tree back all over, so it makes a thicket of water shoots and barely flowers for years.
• Leaving stubs, which die back and carry rot into the trunk.
• Digging or making a border under the crown, so the shallow roots get damaged.
• Pruning in May–July without checking for nests first.

Nearby: related pruning guides

• Star magnolia
• Southern magnolia
• Japanese flowering cherry
• Japanese maple
• Tulip tree

Similar to: Difference from tulip tree

Plant profile: Magnolia · Pruning calendar and basic rules