How to prune a magnolia tree if you want perfect pastel blooms each year

The highlight of the gardening calendar, there's nothing quite like the sight of a magnolia tree in full bloom frothing with large, opulent flowers in pink or white. 

To ensure magnolia flourishes it's a good idea to show these gorgeous shrubs and trees the respect they deserve. When, then, and how should you prune magnolia for tip-top results?

That's right: just as you need to know when to prune lilac and pruning roses, so the same is true of your picture-perfect magnolia, which has remained one of the UK's most enduring garden trends ever since Henry Compton, the Bishop of London, was gifted one from the USA in 1687.

With some 300 varieties of magnolia to fall in love with, of course, it's worth doing your research before you whip out a pair of loppers and get to work – especially if you want to maintain one of your best plants’ health. 

How to prune a magnolia tree or shrub

"It’s important to know which type of magnolia you are growing to ascertain when and how to prune it," explains Morris Hankinson, director of Hopes Grove Nurseries.

"There are evergreen and deciduous varieties (which drop all of their leaves in autumn), and each requires different care."

While evergreen magnolias require very little pruning (you simply want to remove any dead, damaged or diseased wood to keep them healthy, and perhaps do a little shaping if required), a bit more work is required of the deciduous variety.

Morris Hankinson

Morris Hankinson is the founder and managing director of Hopes Grove Nurseries Ltd, the UK’s only specialist grower-retailer of hedging plants. He established the thriving business in 1992, shortly after graduating with a Commercial Horticulture Degree from Writtle College, Essex. 

What you will need

When it comes to gardening, it's always a good idea to make like a Scout and be prepared.

"You will need a pair of clean secateurs, as well as some loppers if you fancy tackling the higher and thicker stems," says Morris.

To that end, then, you should make sure you have the following close at hand:

Step-by-step guide:

Once you have everything you need to prune your magnolia tree, it's time to get started.  To help ensure you do a stellar job, though, cast your eyes downwards and check out what the experts have to advise first...

1) Choose the right moment

It's always important to prune your plants at the correct time, otherwise you can wind up doing more harm than good. Take note of the plants you should avoid pruning in summer.

"Deciduous magnolia trees should be pruned in late summer (usually July), because it reduces the amount they ‘bleed’ when cut, something which can cause infection and disease," explains Morris.

"Make sure the leaves are all fully open and be sure to have the job done by early autumn."

2) Assess the age

Unlike pruning wisteria, there is very minimal skill required when it comes to learning how to prune magnolia, although you will need to tweak what you're doing depending on the age of the shrub or tree.

How to prune a young magnolia tree:

"If you have a young magnolia, use sharp secateurs to cut out dead, diseased or damaged growth – anything that looks particularly weak," says Morris.

"Then, use a pruning saw to remove any bigger stems or branches that are crossing, ensuring a clean, sharp cut. 

How to prune a mature magnolia tree:

As well as ticking off all of the above, Morris says that, "If you have a mature Magnolia tree, you might see shoots that grow upwards called ‘watershoots’ which should also be removed so the tree doesn’t use up energy trying to grow shoots". 

"Cut these all the way back to the trunk," he says, cautioning gardeners to avoid giving their magnolia the same sort of hard prune they would when pruning buddleia. 

In fact, he says it’s best to avoid pruning established trees unless absolutely necessary (such as a need to limit the size of your tree).

"Don’t forget to water and mulch after pruning," he adds.

FAQs

When should magnolia trees be pruned?

Deciduous magnolia trees should only be pruned between mid-summer and early autumn (July is optimal), while evergreen varieties should be tackled in spring, as growth begins.

The exception to the rule? If you have a wall-trained evergreen magnolia, tackle the job in the summer, as per the advice offered by experts at the Royal Horticultural Society (RHS).

That being said, they suggest you "delay pruning until immediately after flowering" if the outward-growing shoots bear flower buds.

Can I cut the top off my magnolia tree?

It is rarely advisable to cut the top off a magnolia tree, as these shrubs and trees are prone to bleeding sap – something which isn't just unsightly, but a harbinger of ill health for your plant, too.

"Usually you will only need to prune out any dead, diseased or damaged wood of magnolia trees because they are very easy to maintain," promises Morris Hankinson of Hopes Grove Nurseries.

"Occasionally you may want to improve the shape, but this should be done over a few years rather than all in one go to reduce stress on the magnolia tree."

Now that you know how to prune magnolia – very minimally and rarely, essentially – you can get back to the very important job of gazing at yours in wonder and marvelling at its timeless beauty.

Hey, there's a reason these shrubs and trees can boost property value, after all.