Panicled hydrangea: when and how to prune

Panicled hydrangea: when to prune it?

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Prune at the end of winter, in March, before the new shoots break. Until then, leave the dry flower heads on: covered in hoar frost or snow, they make a fine winter picture.

Prune on a dry day and not in a hard frost. It is very hardy: a night of frost after pruning does it no harm.

Prune a standard panicle hydrangea at the same time: cut last year’s shoots back to 2–3 pairs of buds above the head.

What else to prune in those months? March

Panicled hydrangea: how to prune it?

1. Cut every stem from last year back to 2–3 pairs of buds, just above a pair of buds. That way the shrub builds up a sturdy framework of branches, from which new flowering shoots grow every year.
2. The harder you prune, the larger but fewer the flower heads. Prune less hard, to 4–5 pairs of buds, and you get more, smaller heads on sturdier stems.
3. Remove thin, weak and dead twigs, as well as branches growing inwards or across each other: that keeps the shrub open.
4. On an older shrub, saw one or two of the oldest, thickest branches off at the base, so young branches can take their place.
5. If the branches bend to the ground after heavy rain, prune less hard the following year, or loosely tie the shrub up.
6. Keep prunings away from rabbits and other pets that nibble: like every hydrangea, it is mildly poisonous.

How much to cut, and how often?

• One prune a year. Pruning every year is better than every few years: without pruning the shrub makes lots of thin twigs with small flower heads.
• A neglected, overgrown shrub can be cut back hard in one go, to a framework 50–100 cm high: it will still flower that summer.
• If you want a large, loose shrub, prune lightly: only remove weak twigs and cut the old flower heads back to the first pair of fat buds.

What does it mean for wildlife?

• The small, fertile flowers in the head attract bees, bumblebees and hoverflies from July to September; the large white outer florets are sterile and only serve as a lure.
• The March prune may fall in the nesting season (15 March–15 August): if you prune after mid-March, first check that no blackbird or dunnock is nesting in the shrub, as disturbing an active nest is against the law.
• Leave the dry flower heads on until you prune: spiders and small insects shelter in them over winter.
• Prunings can go on a dead hedge in a corner of the garden: a shelter for hedgehogs, wrens and insects.

Common mistakes

• Only giving it a timid trim, as you would a mophead: it then becomes tall and untidy, with small flower heads.
• Cutting back to exactly the same height every year without ever removing old branches, so thick, knobbly heads form.
• Pruning too late in spring, when the new shoots are already long: you cut off growth and it flowers later.
• Pruning without checking for nesting birds first.

Nearby: related pruning guides

• Hydrangea
• Smooth hydrangea (Annabelle)
• Oakleaf hydrangea
• Butterfly bush
• Climbing hydrangea

Similar to: Difference from hydrangea

Plant profile: Panicled hydrangea · Pruning calendar and basic rules