How to prune a hydrangea in spring

Most hydrangeas are pruned in spring, between February and April. Leaving their flower heads on over winter helps protect the stems and buds from frost. Climbing hydrangeas are the exception to this rule – they are pruned in summer, after flowering.

Pruning prevents hydrangeas becoming woody and congested, and channels the plants’ energy into producing strong growth and large blooms. Choose a dry day to prune, if possible, as rain can spread disease from plant to plant into open cuts. After pruning, mulch the plant with well rotted manure or compost.

Different types of hydrangea are pruned in different ways, as some flower on old wood and some on new. Pruning incorrectly will affect flowering. Hydrangea macrophylla, Hydrangea aspera, Hydrangea serrata and Hydrangea quercifolia are lightly pruned by cutting back the old flower heads to a pair of buds below. Hydrangea paniculata and Hydrangea arborescens can be cut back harder.

If you’re not sure which type of hydrangea you have, it’s best just to deadhead it and observe how it grows. If you notice that it produces flowers on this year’s growth, you can prune it harder next year.

Find out more about how to grow hydrangeas, and if you’d like to grow more hydrangeas in your garden, be inspired by our pick of nine of the best hydrangeas to grow.

Pruning hydrangeas: jump links

• Pruning mophead and lacecap hydrangeas
• Pruning Hydrangea serrata, H. aspera and H. quercifolia
• Pruning Hydrangea paniculata and Hydrangea arborescens

Mophead and lacecap hydrangeas

Mophead and lacecap hydrangeas (Hydrangea macrophylla) flower on the previous years’ growth. They are an exception to the rule that says shrubs that produce their flowers on the previous season’s growth should be pruned after flowering. The structure of hydrangea stems means that it’s best to leave cutting back until spring. This is because the stems are cork-like, rather than woody, and hold enough moisture inside them during winter for this to freeze in frosty weather. If they are pruned in autumn, after flowering, the buds can freeze, killing the stems and their buds. Leaving the old flowers on the plant over winter, until the worst frosts are over, will help protect the stems and their new buds. Once the sap starts to rise in spring, these buds will open and many should go on to carry blooms the following year.

Remove last year’s flowerheads

[image id=”31465″ size=”landscape_thumbnail” title=”Deadheading mop head hydrangea. Sarah Cuttle” alt=”Deadheading mop head hydrangea. Sarah Cuttle” classes=””] Deadheading mophead hydrangea. Sarah Cuttle

In April, remove old flowerheads to just above a pair of buds. Hydrangea buds can be easily knocked off, so cut carefully using the tips of your secateurs. If the plant has many stems, cut at an angle between the buds to remove one of the pair. This will direct growth into one shoot rather than two, preventing the plant from becoming congested.

Cut out thin, weak stems

[image id=”25100″ size=”landscape_thumbnail” title=”Pruning out weak stems. Sarah Cuttle” alt=”Pruning out weak stems. Sarah Cuttle” classes=””] Pruning out weak stems. Sarah Cuttle

Cut out any thin, weak stems around the base of the plant and remove one or two of the largest, oldest stems from as low down as possible to promote new shoots from the base. These will grow over the next few years and carry blooms in the future.

If you have an overgrown plant, cut some of the stems right to the base. 

Hydrangea aspera and Hydrangea serrata

Hydrangea aspera, Hydrangea serrata and Hydrangea quercifolia are also lightly pruned in spring – just remove old flower heads and old, crossing or long stems in a similar way to mopheads and lacecaps.

Hydrangea paniculata and Hydrangea arborescens

[image id=”38974″ size=”landscape_thumbnail” title=”Hydrangea paniculata ‘Phantom’. Sarah Cuttle” alt=”Hydrangea paniculata ‘Phantom’. Sarah Cuttle” classes=””] Hydrangea paniculata ‘Phantom’. Sarah Cuttle

Hydrangea paniculata and Hydrangea arborescens produce flowers on new wood, which means that you can cut them back harder without losing this year’s flowers. Pruning is not essential, but left unpruned the plant will get taller, with most of the flowers at the top. Watch our expert guide to pruning Hydrangea arborescens ‘Annabelle’.

Cut back to a healthy framework

Cut back in early spring, pruning last year’s growth back to a healthy framework that’s between 30cm and 60cm high. Prune to just above a pair of healthy buds on each stem. Cut back to the lowest healthy buds for big flowers or less hard for a natural look or a taller plant.

Watch Monty Don explain the different ways of pruning hydrangeas in spring:

Pruning climbing hydrangeas

Climbing hydrangeas such as Hydrangea anomola subsp. petiolaris and Hydrangea seemannii should not be pruned until after they have flowered, in summer. 
Need a new pair of secateurs? Read our indepth guide to the best secateurs so you can buy in confidence. 

Common issues when pruning

The main issues when pruning hydrangeas are:

• Pruning at the wrong time of year – check the type of hydrangea you have before pruning. They all have individual needs – see above for how to prune the variety of types. Pruning in winter can lead to frosted stems.
• No flowers – pruning a hydrangea that flowers on old wood too vigorously or at the wrong time of year can lead to a lack of flowers
• Overgrown shrub – a lack of regular pruning can lead to an overgrown hydrangea, which will then need a hard prune. Hard pruning can reduce flowering so it’s better to keep on top of annual pruning

Frequently asked questions

What is the best month to prune hydrangeas?
The best month to prune most hydrangeas is between February and April, but climbing hydrangeas should be pruned after flowering, in August or September.

Do hydrangeas need to be cut back for winter?
No, hydrangeas have cork-like stems which can hold moisture. If pruning cuts are made in autumn or winter, the cuts can freeze which will kill stems and buds.

What month do you deadhead hydrangeas?
It’s better to leave the flowerheads on hydrangeas to protect the shrub’s stems over winter. Lacecap hydrangeas are hardier than mophead types and can be deadheaded after flowering, but it would be best to do this no later than August, cutting back to just above a pair of leaves.

Can hydrangeas be cut back hard?
Cutting hydrangeas back hard will affect the amount of flowers it has the following year, for those types that flower on old wood. The reasons you might want to cut back hard are if your hydrangea is overgrown. In this case, you can cut all stems to the base to encourage new stems to grow, but these will not produce flowers until the following year. Alternatively, prune out one or two stems to the base annually, rejuvenating the shrub over a few years. Climbing hydrangea can also be cut back hard in the spring, but this may also affect its flowering.