Pruning hydrangeas in autumn When beauty gets out of hand

Hydrangeas are one of those garden favourites that make it hard to pick up the secateurs. Big, beautiful blooms that last for months — they bring a lot of joy to the garden. But in a mild, damp coastal climate, they can grow way too well. Before you know it, that neat shrub has turned into a shoulder-high thicket, flopping over paths and shading out everything nearby.

It’s always a bit painful to make the first cut, especially when the flowers are still hanging on. But regular pruning is what keeps hydrangeas healthy, compact, and full of new growth for next year’s display.

When to prune

Autumn pruning be tricky. Our weather tends to stay mild and wet right into November, which encourages late growth. The safest time to start is once the flowers have faded and the first real frosts are due — usually late October into November. Cutting too early can stimulate new shoots that are easily damaged by cold and wind.

If your hydrangea has completely taken over, don’t worry — it’s possible to bring it back into shape gradually.

How to prune: step by step 

1.) Start by removing the spent blooms.

Focus on tidying up the plant. You'll remove spent blooms, as well as any dead, damaged, or weak stems. Also look for any crossing branches that may rub against each other and create wounds.

Remove the spent blooms. Cut just above a pair of strong buds lower down the stem. This tidies the plant while leaving protection for those buds over winter.

For dead or weak stems, cut them back to the base of the plant or to a strong outward-facing bud.

2.) Thin out old, woody stems.

Every year, take out a few of the oldest, woodiest stems right at the base — about a third is a good rule of thumb. This opens the plant up and encourages strong, fresh growth next season.

When cutting, always try to make your cuts at a slight angle.

For shaping or reducing the size, cut back to a main stem or an outward-facing bud.

3.) If it’s truly overgrown…

You can go harder. Cut the whole shrub back to about 30–40cm (a foot or so) from the ground. It will look brutal, but hydrangeas are resilient. Expect fewer flowers the following summer, but a much neater shape.

A few smart choices now and you’ll have a garden that keeps its colour, even when the hosepipe stays in the shed.

Not All Hydrangeas Are the Same 

Your approach depends entirely on what kind of hydrangea you have, as some bloom on "old wood" and others on "new wood." 

Hydrangea macrophylla (mophead and lacecap types) flower on old wood, so avoid cutting all stems down in one go — you’ll lose next year’s blooms. Stick to removing spent flowers and a few old stems.

Hydrangea paniculata and H. arborescens flower on new wood, so they can be pruned harder — right back to 30–50cm each autumn.

Hydrangea quercifolia (oakleaf) prefers light pruning only, just removing dead or damaged growth.

If you’re not sure which type you’ve got, wait until late spring before doing any heavy pruning — the emerging buds will tell you where it flowers.

So in conclusion...yes, it can be hard to make that first cut on a beautiful hydrangea, but once it’s done, you’ll be rewarded with a stronger, tidier shrub and bigger, better blooms next summer!