The Best Time to Prune Hydrangeas

Hello, my name is Hannah Miller, and I’m the co-owner and contributor here at DIY Gardening.

In this blog post, I’ll quickly explain how and when to prune hydrangeas, so they come back strong with lots of healthy flowers, year after year.

There are several types of hydrangeas, so let’s start with the climbing hydrangea.

Climbing Hydrangea

The climbing hydrangea (Hydrangea petiolaris) should only be pruned immediately after it’s finished flowering, which is usually in the summer.

In my experience, it’s best to prune back to a set of buds – cut off all the buds, and the hydrangea won’t flower next year or will flower, but very poorly.

The buds on climbing hydrangeas usually form at the top of the plant, so if you have an overgrown specimen, you have two options:

1. Prune lightly and in stages over several years to get it back under control.
2. Prune hard and sacrifice the flowers for the next year.

It’s not absolutely necessary to prune this hydrangea every year but it’s likely to grow wayward quickly if left unpruned for several years.

Hydrangea Paniculata

I grew this hydrangea at my previous address, and I found it best to prune it in early spring using one of these methods:

• Remove weak stems and prune the remaining, leaving 2-3 sets of buds on each.
• Prune back to a solid framework of thick stems, ensuring some buds remain.

I forgot to prune this hydrangea for two years and while it still produced plenty of blooms, they were noticeably smaller.

You can use this as a general rule of thumb:

Don’t prune – more flowers that are smaller.

Remove weak stems and prune the remainder to 2-3 buds – a good compromise, plenty of blooms that big.

Prune hard, leaving very few buds – won’t produce many blooms that year.

Hydrangea Macrophylla (Mopheads and Lacecaps) + Oakleaf Hydrangeas

These hydrangeas can be left unpruned but in my garden, they grew leggy with weak stems that bent under the weight of the flowers.

I’ve found through trial and error that aggressive pruning should be avoided as the flowers bloom on the previous years’ growth. Prune this off, and the Macrophylla won’t flower until the following year.

You have three options:

1. Prune after flowering in the autumn; remove weak stems and prune other stems lightly, making sure not to prune off all the buds. Consider pruning out 10-20% of the thicker stems at the base to encourage new growth.
2. Wait until the spring and then prune. The old flowerheads offer frost protection and this method is best suited to hydrangeas grown in colder areas. Be careful not to nip off too many buds.
3. Aggressively prune to just above the base or a low framework after flowering or in the spring. The hydrangea should recover but probably won’t flower until the following season. I only suggest this option if you have a wayward shrub that you want to get under control quickly.

The oakleaf hydrangea prefers a lighter prune, and I’ve found the best method is to snip off 10-20% of the older stems at ground level to encourage new growth.

Hydrangea Arborescens

I have experience with this hydrangea and I’ve always found it very forgiving.

I’ve had great results by pruning hard in early spring, either down to a frame 25cm above the ground for fewer but larger blooms or down to 50cm for more numerous but smaller flowers.

Hydrangea arborescens should recover from a hard prune, so don’t be afraid to hack it back to a framework of thick stems.

If left unpruned, this hydrangea will grow leggy very quickly – you’ll see more blooms, but they will be noticeably smaller.

Other Hydrangea Guides

I think you’ll also find these articles and guides insightful:

The best feed for hydrangeas

How to propagate hydrangeas (100% success rate)

5 reasons your hydrangeas aren’t flowering

How to grow hydrangeas in pots