How to Prune Hydrangeas

Daniel Woodley

Find Out Which Hydrangea You Have

Some hydrangeas perform best when pruned lightly and won’t tolerate pruning mishaps; they may even refuse to produce any blooms until the following year. Others prefer aggressive pruning and can look leggy and sparse unless pruned hard.

Don’t worry if this all sounds confusing; our guide is easy to follow and guarantees success.

Hydrangeas can be split into five categories, and they are all pruned differently:

Hydrangea Macrophylla – also known as the “big leaf” variety. There are three types of macrophylla; lacecaps, mopheads and mountains.

Oakleaf – the only hydrangea that produces leaves similar in shape to oak leaves, just bigger.

Paniculata – long panicles containing clusters of flowers make this hydrangea distinct and easy to identify.

Aborescens – large leaves and large globe-like flowers make this hydrangea stand out from the crowd.

Climbing – the only hydrangea to climb, and it can reach 20 metres. It produces small clusters of lacecap flowers, usually white.

Here are some photos to help you identify your hydrangea:

Mountain hydrangea

Aborescens from a wider angle

Climbing hydrangea

How to Prune Hydrangeas

Before you read our guide to pruning hydrangeas, it’s important to understand that some species will produce blooms via buds that formed the previous year.

This type of hydrangea blooms on “old wood”, and the buds are set in autumn; if they survive the winter frost and aren’t inadvertently chopped off, they will form flowers the following summer.

Frost and pruning mishaps are the most common reasons hydrangeas won’t flower, so the gardener should be careful not to prune the “old wood” hydrangeas aggressively.

When to Prune Hydrangea Macrophylla

Hydrangea macrophylla is the shrub that gardeners have the most issues with as it blooms on old wood and isn’t frost resistant.

There are several schools of thought as to how best to prune macrophyllas but one should remember that they don’t always need pruning, for most macrophyllas, it’s optional.

1) Prune immediately after the blooms fade in the summer and well before the plant sets buds for next year’s flowers. This option removes the frost protection that the old blooms would offer if they were left on the plant over winter. However, the gardener is less likely to chop off buds as the plant hasn’t set them yet.

2) Prune lightly in spring after the last frosts. By leaving the old blooms on over winter, the plant will have some frost protection, but aggressive pruning will remove the buds that were set last year, and no flowers will form. This method is more suited to very light pruning and deadheading. If you prune hard in spring, it’s very likely you’ll chop off most of the buds needed for the blooms. Light pruning can be defined as deadheading, trimming off frost-damaged stem tips and pruning out thin, weak stems.

3) As above but remove 10-30% of the stems from the crown of the plant. This method is a great way of reducing the size of a large, wayward hydrangea as it will still flower on the remaining stems whilst producing new stems from the base that will flower the following year and improve density. This method should be repeated for a few years until the hydrangea is at the desired size.

4) Remove all the stems at ground level or just above the crown of the plant in spring. Macrophyllas won’t flower on new growth this year, so this method means no blooms will appear until the following year, but this is the quickest method to get a large, wayward hydrangea down in size.

Note: Climbing hydrangeas should be pruned in summer after the blooms have faded.

Our Advice on When to Prune Hydrangea Macrophylla

If you want to prune your hydrangea macrophylla very lightly, i.e. deadheading and removing thin, weak stems etc., then leave the old blooms on for frost protection over winter and prune lightly in spring after the last frosts.

Want to prune your macrophylla a little more aggressively? Do so after the blooms fade in the summer before the new buds are set.

Want to reduce the size of an overgrown, wayward macrophylla while guaranteeing some blooms? Prune off 10-30% of the stems near the base to encourage new growth. Blooms will still appear on the old stems. Repeat the process over a few years.

Recommended Products

Key Points:

• Bypass secateurs.
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Uses:

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• Long-lasting – lasts up to 10,000 strokes.

Why You Should Use Vitax:

• Made from slow-release pellets.
• Hydrangeas only require 2-3 applications per year.
• Perfect NPK ratio of 8-4-12.
• Added magnesium to produce larger blooms.
• 1kg bags with discounts for bulk buying.
• It won’t change the colour of the flowers.
• Won’t burn the plants as some liquid feeds do when spilt.

Read More:

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The ultimate Hydrangea Growing Guide

5 reasons your hydrangeas aren’t flowering

How to grow hydrangea macrophylla “ab green shadow”

A step-by-step guide to taking and growing hydrangea cuttings

Seeing yellow hydrangea leaves? This is the solution but act quickly

Causes and solutions of hydrangea leaf spot