How to Prune Hydrangeas

March 8, 2017

With some hydrangeas blooming on old wood and others blooming on new wood, it can be confusing which ones to prune and when to prune them.

To start off with, hydrangeas, in general, do not have to be pruned to keep them healthy. But, if you like to keep them clean and tidy or if your hydrangea has started to outgrow its space, take a minute to read through these tips about pruning hydrangeas before you get your shears out.

Tip #1: You can leave old blooms on the stems, but if you don’t like that look, you can deadhead spent blooms and remove dead and/or weak branches.

Tip #2: For hydrangeas that bloom on old wood, these can be pruned right after the flowers fade, or in late winter by cutting off only the spent flowers. If you prune these hydrangeas back too far, you may cut off the buds which would mean no flowers and we don’t want that! These hydrangeas bloom on old wood:

  • Hydrangea macrophylla (Big Leaf Hydrangeas)
Hydrangea macrophylla 'Nikko Blue' (Nikko Blue Hydrangea)

Hydrangea macrophylla ‘Nikko Blue’ (Nikko Blue Hydrangea)

  • Hydrangea quercifolia (Oakleaf Hydrangeas)
Hydrangea quercifolia 'Snow Queen' (Snow Queen Oakleaf Hydrangea)

Hydrangea quercifolia ‘Snow Queen’ (Snow Queen Oakleaf Hydrangea)

Tip #3: On the flip side, there are hydrangeas that bloom on new wood meaning that buds form during the current season and you don’t have to worry about cutting off blooms as long as you prune them early. These ones should be pruned in later winter to early spring before new growth appears. These hydrangeas bloom on new wood:

  • Hydrangea paniculata (Panicle Hydrangeas)
Limelight Hydrangea (Hydrangea paniculata 'Limelight'_

Limelight Hydrangea (Hydrangea paniculata ‘Limelight’

  • Hydrangea arborescens
Hydrangea arborescense 'Annabelle' (Annabelle Smooth Hydrangea)

Hydrangea arborescens ‘Annabelle’ (Annabelle Smooth Hydrangea)

Tip #4: There are always exceptions to the rules. If you have a continually blooming variety of hydrangea, these will have flowers on new and old wood. ‘Endless Summer’ is a popular rebloomer.

Hydrangea macrophylla 'Twist and Shout' (Endless Summer Twist and Shout Hydrangea) Photo Courtesy of Endless Summer Blooms

Hydrangea macrophylla ‘Twist and Shout’ (Endless Summer Twist and Shout Hydrangea) Photo Courtesy of Endless Summer Blooms

Tip #5: When pruning old wood blooming hydrangeas, cut out any dead or weak branches and intersecting branches then focus on thinning cuts to let in more sunlight to the interior of the plant.

Tip #6: New wood blooming hydrangeas follow the same process of pruning out weak or dead and intersecting branches first. After that, you can choose which stems to prune in order to help shape the plant or control its size.

Tip #7: For continually blooming hydrangeas, you should cut blooms right after they have faded in late spring/early summer. After the last flowers have faded in winter, you can prune the whole plant if you need to control shape or size. Again, start by removing any dead or weak branches and intersecting ones and then selectively prune other branches.

Before Pruning

Before Pruning

After Pruning

After Pruning

The most important thing is to know what kind of hydrangeas you have and whether they bloom on old or new wood. Once you know that information, hydrangeas are pretty simple to prune. We hope this has answered your hydrangea pruning questions and you feel better about heading outside and getting your gardening on!

Do you have other plants that you’re not sure what, when, or how to prune? Ask us in the comments below!

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