How to prune hydrangeas – top tips for healthy plants and more flowers

Popular flowering shrubs, we must learn how to prune hydrangeas correctly to get the best from them, maximize blooms and to ensure that they can survive through winter. 

Hydrangeas make a great statement piece in a bed, border or in containers. They put on a spectacular display of flowers in the summer, and then die back in winter. Tolerant of a wide range of soil and light conditions, apart from a little pruning, hydrangeas require almost no maintenance. 

While learning how to grow hydrangeas is relatively simple – make sure you know when to plant hydrangeas and when to prune hydrangeas too – they can be disappointing over time if they are not correctly maintained through pruning and deadheading. Luckily, this is an easy skill to learn.

They range in color from white to pink, pale blue to deep purple. Their large, clustered flower heads, made up of lots of smaller flowers, make them a highly attractive and decorative plant, and there are many choices for what to plant with hydrangeas. Some of the flower heads are also wonderful for enduring floral displays indoors if you learn how to dry flowers. 

The way that you prune your hydrangea will depend on the variety that you have. Here we will look at the different types and how to prune them hydrangeas.

How to prune hydrangeas – for beginners

Hydrangeas are generally pretty low maintenance shrubs, and among the best flowering shrubs. Once you have identified the variety that you have in your garden, it's easy to get to grips with how to prune hydrangeas. 

Some of these fast growing shrubs flower on old wood and some on new wood, so it is important to prune them the correct way so as to not detrimentally affect their flowering. 

'Pruning hydrangeas will help the formation of new flowers and promote good shape,' explains Ian Wright, garden consultant at National Trust , which boasts dramatic displays of hydrangeas in many of its gardens as flower bed ideas.

Pruning mophead hydrangeas and lacecaps

The method for pruning mophead hydrangeas and lacecap hydrangeas (Hydrangea macrophylla)  – also known as bigleaf hydrangeas – is the same.

Mophead hydrangeas are a common choice for gardens with their full, roundish heads of large petals in shades of blue, pink, green and white. This makes them a popular shrub choice for cottage garden ideas and they also make good shrubs for shade.

Lacecap hydrangeas are identified by tiny flowers in the center of the bloom and an outer border of larger petals.

These varieties should be pruned in late winter or early spring. 

As a way to winterize hydrangeas, 'it’s best to leave the faded blooms in place over the winter to protect tender new buds from frost damage,' advise the experts at Thompson & Morgan

When pruning mophead hydrangeas and lacecaps in early spring:

• Cut out one or two of the oldest, weakest stems at the base of the plant to encourage new growth that will have better blooms.
• Using secateurs, carefully remove old flowerheads just above a pair of buds.
• Be careful not to cut off any of the flower buds.
• If the bigleaf hydrangea shrub has been neglected and has lots of overlapping, tangled branches, you can do a harder prune and cut the stems down to the base of the plant. However the hydrangea will then not bloom until the following year.

How to prune climbing hydrangeas

Climbing hydrangeas, such as Hydrangea anomola subsp. petiolaris, Hydrangea seemannii or H. serratifolia are pruned in summer, after flowering.

The reason that climbing hydrangeas are pruned in summer is because the flowers are produced on the previous year's wood. If they are pruned earlier in spring, before flowering, the blooms for that year will be sacrificed. 

'Prune Hydrangea petiolaris immediately after flowering to shorten any branches growing out from the wall or support, otherwise only light pruning is required to remove dead or damaged stems,' advises gardening expert Sarah Raven.

Most flowers appear at the top of these flowing climbers, so the RHS advise to leave as much of this unpruned as possible.

How to prune Hydrangea paniculata and Hydrangea arborescens

Hydrangea Paniculata with its cone-like heads of blooms, and Hydrangea aborescens with its spherical flower heads, are also pruned in early spring.

• They produce flowers on new wood, so they can be pruned back harder without sacrificing that year's flowers.
• Prune old branches back to the lowest pair of healthy buds near ground level for a neat framework.
• 'By cutting stems to different heights, you’ll get flowerheads produced at different levels,' advises Sarah Raven

Other types of hydrangea, including Hydrangea aspera and Hydrangea quercifolia, need only light pruning in spring. Simply remove dead flower heads and overlong or crossing stems.

What happens if you don't prune hydrangeas?

If you don't prune hydrangeas then they can eventually resemble a tangled mass of woody stems, and the flowers will become smaller and less showy. If your hydrangeas are not blooming, lack of pruning is often a reason.

Regular pruning of hydrangeas helps to maintain their shape and also encourages new growth and a better display of blooms. 

'It's this strong, new growth that ensures you have lots of large, healthy flowers to enjoy in the years to come,' explain the experts at Thompson & Morgan.

Do you cut off dead hydrangea blooms?

Deadheading hydrangeas – or removing spent flowers from the stem to encourage better blooming later on – can be done with some hydrangeas but not all.

The RHS recommends that dead blooms should only be removed from mophead hydrangeas after flowering in mild areas. Their advice is that it is better to leave the flowerheads on the plant over winter to provide some frost protection. 

In addition, by leaving the dried flowers on the plant, they will provide interest in the garden through to spring, and can be a stunning sight when covered in a coating of frost.

The flowers on the hardier lacecaps, however, can be deadheaded after flowering.

How far back should you prune hydrangeas?

Hydrangea macrophylla, Hydrangea serrata, Hydrangea quercifolia, and Hydrangea aspera can be cut back, in spring, as far as the first pair of buds. You are essentially removing the dead flower heads. You can also open the plant up a little and improve its shape by cutting back one or two of the oldest, largest stems. Cut these back right to the ground to encourage new growth. 

Hydrangea aborescens and Hydrangea paniculata produce flowers on new growth and can therefore be cut back harder after flowering. You don’t actually need to prune these varieties, but you can do it to keep them from getting too tall. 

What is the best way to prune hydrangeas?

The best way to prune hydrangeas, as with all pruning, should be carried out with a sharp, clean pair of gardening tools. This is to create a clean cut that is less prone to infection. The way that you prune your hydrangea will depend on the variety that you have, and to some extent the condition of the plant. 

If you find that your way of pruning is not yielding good blooms or a healthy plant, you may want to change your approach. Observe your plant through spring and summer to determine where it flowers from, old or new growth. Then prune according to this guide. 

This feature was created by H&G sister brand, Period Living magazine

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