Can I prune my hydrangeas yet?

“When should I prune my hydrangea?” is one of the most frequently asked gardening questions.

At this time of year, although pretty in frost, the old flowerheads can start to look a little, well, scruffy. And the urge to tidy is strong.

So can you cut them back now? The answer is maybe...

The key is knowing which hydrangea you have. Below is a simple guide to the most common types and and when to prune them.

Mophead & Lacecap Hydrangeas

(Hydrangea macrophylla)

These are the classic hydrangeas with big rounded (mophead) or flatter, lacy (lacecap) flowers, usually pink, blue or purple.

When to prune:

Late winter to early spring, once the worst frosts have passed. Leaving the old flowerheads gives some protection to the developing buds from the worst of any winter cold.

How to prune:

• Remove any dead, diseased or damaged stems completely.

• Look for the first pair of healthy buds below each spent flower head and cut just above those buds.

• If the plant is congested, you can remove up to 1/3 of the oldest stems at the base to open it up.

  
  

Mopheads and lacecaps flower on old wood (last year’s growth). Heavy pruning risks losing this year's flower buds.

Smooth Hydrangeas

(Hydrangea arborescens, e.g. ‘Annabelle’)

These have large, rounded flower heads, usually white, and tend to be very vigorous.

When to prune:

Late winter to early spring - when dormant.

How to prune:

• These can be cut back hard.

• Reduce stems to around 30–45cm (12–18 inches) from the ground - this will result in a shorter plant with larger blooms.

• Alternatively, cut back lightly if you prefer a taller shrub with smaller flowers.

• Remember, always remove any dead, diseased or damaged stems as a first step.

  
  

Smooth hydrangeas flower on new wood (this year’s growth), so pruning encourages strong new stems and good flowering.

Panicle Hydrangeas

(Hydrangea paniculata e.g. 'Limelight' or 'Pinky Winky')

These have cone-shaped flowers and tend to be shades of white, light pink or even pale green.

When to prune:

Late winter to early spring.

How to prune:

• You can treat these the same way as Hydrangea arborescens

Like smooth hydrangeas, paniculatas flower on new wood and respond well to pruning

Climbing Hydrangeas

(Hydrangea anomala subsp. petiolaris)

These are slow to get going but eventually become large, impressive climbers with white lacecap-style flowers.

When to prune:

Only if needed, and ideally after flowering in summer.

How to prune:

• Remove dead, diseased or damaged growth.

• Lightly trim to keep within bounds.

• Avoid heavy pruning unless absolutely necessary.

  
  

Climbing hydrangeas flower on old wood, and excessive pruning can reduce flowering for several years.

Not Sure Which Hydrangea You Have?

If in doubt, leave it alone. Leaving a hydrangea unpruned for 1 year will do no harm and will give you a chance to identify it properly when it comes into flower in summer.

Image credits:

Annabel: Image by Hans Linde from Pixabay

Blue: Image by Couleur from Pixabay

Panicle: Image by Manuela Hartmann from Pixabay

Climbing: Image by Kerstin Riemer from Pixabay

Dead flowerhead: Image by Heike Tönnemann from Pixabay