Hydrangeas: how to prune these beautiful shrubs

Hydrangea flowers

In this article I show you how to prune hydrangeas, with a simple step by step process.

There are multiple species of hydrangea and many different varieties or cultivars within each species. This means, it is pretty easy to find a hydrangea to suit your garden.

Hydrangea flowers

Hydrangeas are grown for their showy flowers. When we prune hydrangeas, it is generally so as to ensure that we get the best flower displays each summer. Therefore it is important to understand all about hydrangea flowers before we learn about the pruning techniques.

Hydrangea species tend to have flowers of different shapes. This is one of the distinguishing features. Thus:

  • Hydrangea microphylla (hortensia) or Hydrangea arborescens have round ‘mophead’ flowers;
  • Hydrangea microphylla, Hydrangea serrataHydrangea villosa or Hydrangea aspera have ‘lacecap’ cultivars, which have flatter flower heads with mini flowers in the centre and larger flowers on the outside, and
  • Hydrangea paniculata or Hydrangea quercifolia have cone-shaped flowers.

One of the other distinguishing features of hydrangeas is their flower colours. We typically see pink, blue, mauve, white or green flower colours on hydrangeas. The pink/blue cultivars tend to have blue flowers where the soil is acidic, pink flowers where the soil is alkaline and mauve flowers where the soil is neutral.

Flower colours of hydrangeas also change over the growing season – white flowers frequently turn pink and blue and pink flowers often fade to shades of green and red.

In fact, what we think of as the flower petals on hydrangeas are actually sepals – outer bracts that protect tiny flowers within. It is the sepals that are coloured and therefore the primary feature of dahlia blooms.

Another important point to remember is that most of the flowers on most hydrangeas are sterile and therefore don’t produce seeds. On mophead dahlias, there are a few fertile seed-bearing flowers in the centre of the bloom, but most of the flowers are sterile. On lacecaps there are more fertile flowers. These are the small inner flowers. The larger outside flowers are sterile.

Hydrangeas – how to prune, step by step

Time needed: 15 minutes.

There are some variations in how to prune hydrangeas according to the different species. Steps 1 to 4 below apply to mophead and lacecap dahlias. Other species are covered in Steps 5 and 6.

  1. Understand how hydrangeas flower

    The important point to remember is that hydrangeas flower on shoots that extend from the previous year’s growth. So if you cut hydrangea stems back too hard you will lose the next season’s flowers.
    hydrangea flowers

  2. Timing

    It is generally best to prune mophead and lacecap hydrangeas in late winter or early spring. It is a good idea to leave the spent flower heads on the plant over winter as this tends to protect the buds of the flowering shoots that are developing lower down on the stem.

    Lacecaps are a little bit hardier, so if preferred their blooms can be removed after flowering. But many people prefer to leave all the dead flower heads on the plant over winter as they provide more visual interest that than the bare stems.winter hydrangea flowers

  3. Cut out dead or congested stems

    Before you cut back the dead flowers in late winter or early spring, it is best cut back any dead stems right to the base. It is also a good idea to take out 1 or 2 stems from the centre of the bush each year to let in more light and encourage fresh growth that will flower in the years to come.

    If a specimen is old or very congested, you can cut all the stems back hard to regenerate the whole bush. But be aware, there won’t be any flowers that year. Instead flowers will come the following year on the current year’s growth.hydrangea - how to prune

  4. Remove spent flower heads

    After you have thinned out the shrub a little, you can remove the spent flowers. Cut the stems just above a pair of healthy buds.

    As the buds begin to break, feed the plant with a balanced fertiliser and mulch it well. This should encourage the new shoots to grow away strongly. pruning hydrangea

  5. Hydrangea paniculata and Hydrangea arborescens

    Hydrangea paniculata and Hydrangea arborescens flower better if given a slightly more vigorous pruning. So, as well as removing any dead or damaged stems, you should prune these back to the lowest pair of healthy buds in spring. Do this across the whole plant, creating a framework of stems 2-3 feet high (30 to 60 cm). This should produce strong healthy branches and large flower panicles.

    pruning hydrangea

  6. Climbing hydrangea – Hydrangea anomala subsp. petiolaris

    Flowers on the climbing hydrangea mainly appear at the top of the plant, so it is best to leave as much of this unpruned as you can. However, prune back any unruly shoots you do want to remove immediately after flowering.


Conclusion

Follow these steps when pruning your hydrangeas, especially giving them a good feed and mulch at the start of the growing season and you should find you are rewarded with strong healthy plants and beautiful flowers.

What you need

All you really need are a good pair of secateurs. I always use Felco Number 2 secateurs which I have always found to be the best secateurs for any pruning job.

US Buyers

FELCO F2 Professional Pruning Shears with Leather Clip or Belt Holster (Bundle, 2 Items)
  • Bundle – 2 Items: Felco F2 Professional Pruning Shears with Leather Clip or Belt Holster
  • Reliable: comfortable, light, sturdy handles made of forged aluminium with a lifetime guarantee* / blade and riveted anvil blade made of high-quality hardened steel / clean, precise cut / all parts can be replaced
  • Efficient: easy, durable cutting adjustment / wire cutting notch / sap groove
  • This size is for medium to large hands
  • Ergonomic: hand protection is provided by the cushion-shock absorber / non-slip coating
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FELCO F-2 068780 Classic Manual Hand Pruner, F 2
  • Anvil blade with a sap groove
  • A hardened bolt and nut to assure exact adjustment of both the cutting and anvil blades
  • Rubber cushion and shock absorber
  • Ideal pruner for light applications and easily adjustable
  • Features strong blades with a wire cutting notch

Last update on 2022-09-28 / Affiliate links / Images from Amazon Product Advertising API

UK Buyers

Felco Professional Model 2 Secateur

£64.95  in stock
Harrodhorticultural.com
as of September 24, 2022 2:48 pm

The Felco model 2 bypass secateur is a popular and high quality product, used and highly recommended by gardening professionals. It features:

- comfortable lightweight, easy to grip handles,
- a hardened steel blade with a wire cutting notch,
- riveted anvil with sap groove to allow plant fluids to drain away
- a toothed centre nut mechanism which easily aligns the blades for a clean precise cut
- a rubber cushion shock absorber that protects the wrists.

Felco No 2s carry a lifetime guarantee and all parts can be replaced, so it is easy to see why these are the secateurs of choice for many horticulturists and serious home gardeners.

21.5cm/8.5" overall length can cut stems up to 2.5cm/1" in diameter.
Weight 240g/8.5oz

Felco Leather Secateur Holster

£31.95  in stock
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as of September 24, 2022 2:48 pm

The Very Useful Felco Leather Secateur Holster Will Make Sure Youre Quick On The Pruning Draw And Is The Perfect Way To Keep Your Secateurs Safe And To Hand.the Genuine Leather Holster Simply Clips To A Belt, Trousers Or Pocket, Securely Houses The Secateurs At A Convenient Hip Height And A Combination Of Steel Rivets And Heavy Stitching Ensures This Holster Stays Put.the Leather Holster Measures 24cm In Length And 10cm Wide At The Top, Narrowing To 8cm Towards The Bottom And With A Riveted Metal Clip On The Back Are Now Available With An Extra Storage Facility For Your Felco Diamond Steel Tool Sharpener felco Leather Secateur Holsters Measures 24cm In Length10cm Wide At Top Tapering To 8cmfelco 910+ Contains Additional Pocket For Storing Your Felco Steel Tool Sharpener (available Separately)made From Genuine Leatherintegral Metal Clip On Back Attaches To Belt, Trousers Or Pocketsafely Stores Secateurs At Hip Heightconvenient When Plenty Of Pruning Requiredhelps Prevent Secateurs Being Lost Or Misplacedheavy Duty Stitching And Metal Rivets In Construction

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US Buyers

Annabelle Hydrangea

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Long Season of Beautiful Blooms Annabelle Hydrangea Huge White Flower Heads Bloom Last through Summer, Fall and Winter Very Dependable Performance Cut and Dried Flowers Make Incredible Indoor Decorations Sophisticated Classic Easy to Grow Adaptab

Fire Light Hydrangea

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Gorgeous Hardy Hydrangea Fire Light® Hydrangea Full Sun or Light Shade Cold Hardy Flowers Change Colors Over the Whole Growing Season Massive Flower Panicles Transform from Pure White to a Rich Pink Sun Loving, Easy to Grow Hydrangea Winter Inter

Little Quick Fire Hydrangea

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Big Flower Power Little Quick Fire® Hydrangea Very Early Bloom Time Compact Shrub with Full-Size Flowers Cone-Shape Flowers Start Snowy White And Deepen to Bold Rose-Pink Great "Thriller" in Containers Enjoy Cut Flowers Fresh or Dried Sturdy Stem

Pinky Winky Hydrangea

$69.99  in stock
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Giant white and pink spires on a hefty strong plant, the Pinky Winky® Hydrangea, (Hydrangea paniculata 'DVPPinky') has astonishingly large blossoms that grow up to 14" in length! Each floret has nearly double the petals of other Hydrangeas, giving the

Limelight Hydrangea

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Easy, Sophisticated Elegance Limelight Hydrangea Favorite of Garden Designers Fresh, Clean Flowers Last and Last Extremely Reliable Easy Care Versatile and Hardy Fabulous Cut Flowers Award Winner Well known as a garden rock star, the Limelight

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Hydrangea paniculata 'Pinky Winky

£41.99  in stock
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as of September 24, 2022 1:47 pm

Hydrangea paniculata are tough, hardy, weatherproof shrubs which can give big impact in borders, and can last for many years.

Hydrangea arborescens 'Strong Annabelle

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as of September 24, 2022 1:47 pm

As its name suggests, Hydrangea arborescens 'Strong Annabelle' is a sturdier cultivar of the well loved 'Hydrangea 'Annabelle'. The enormous, rounded heads of white florets stand proud on the strong stems of this deciduous shrub, even in exposed positions. Unlike many Hydrangea arborescens varieties, this well branched Hydrangea rarely flops due to its well branched, compact growth habit.

Hydrangea macrophylla 'Endless Summer - Bloomstar

£82.99  in stock
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as of September 24, 2022 1:47 pm

Hydrangea macrophylla 'Bloomstar' flowers from May until September and throughout these months this shrub is full of beautiful flowerheads, each measuring up to 13cm in size, that grow on bright red shoots. What is fascinating about this Hydrangea is that the colours of the flowers depends on the pH of your soil. If the soil is acidic the petals will be violet blue and if the soil is alkaline, then the petals will be mauve pink. In autumn the foliage turns to shades of red and gold, whilst the papery flowerheads slowly begin to skeletonise, which look amazing on frosty mornings. 'Bloomstruck' has a sturdy growth habit and is mildew resistant. This neat, compact shrub is extremely low maintenance and looks great in garden borders, or planted in large patio containers. Height: 120cm (48). Spread: 150cm (60).

Hydrangea macrophylla 'Blue Danube

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Hydrangea are one of the easiest shrubs to grow, and will perform extremely well in gardens up and down the UK.


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Check out my comprehensive step by step guide, with plain language explanations and ultra-useful images and illustrations. This is for you if you love dahlias and want to the best out of the dahlias you grow.

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