Do I Need to Prune My Hydrangeas Now?
Depending on where you live, things are starting to come alive in the garden. Maybe it’s still chilly in your neck of the woods, and the crocuses are just starting to make a show with their pretty purple flowers. Or it’s already warmed up a little, so your tulips have come and gone, and the Snowball viburnum is about to pop. Either way, you want to take this time to prune your hydrangeas—or not!
That may sound cryptic, but to get the most blooms on your hydrangea plants, there are a few hard-and-fast rules to follow when it comes to pruning.
How Do I Know if I Should Prune My Hydrangeas Now?
First, you need to determine what type of hydrangea you have. Some types bloom on old wood and some on new wood.
Hydrangeas that bloom on old wood—meaning flower buds form on the previous year’s growth—should be pruned in the late summer after that year’s blooms are spent. Avoid pruning in the fall, winter, or spring, as you will remove the flower buds that are set and ready to bloom that year. These types of hydrangeas require only light pruning to help maintain the shape of the plant, remove any dead wood, and thin out any crowded or crossing branches.
Examples of hydrangeas that bloom on old wood include:
• Bigleaf hydrangeas (Hydrangea macrophylla)
• Oakleaf hydrangeas (Hydrangea quercifolia)
• Climbing hydrangeas (Hydrangea anomala)
Hydrangeas that bloom on new wood should be pruned in late winter and early spring—aka now! These types produce their flower buds on wood that grows in the current season. While you can prune these types in the late fall after the plant has gone dormant, you run the risk of weakening the plant, so it’s best to wait. These types can be lightly pruned to remove any dead wood and to shape the plant, or heavily pruned if you want to control the size or get rid of spindly branches. It’s safe to remove about one-third of the plant when pruning.
Examples of hydrangeas that bloom on new wood include:
• Panicle hydrangeas (Hydrangea paniculata), including the ever-popular Limelight hydrangea
• Smooth hydrangeas (Hydrangea arborescens), which include varieties like Annabelle and Incrediball
How Do I Know What Type of Hydrangea I Have?
The easiest way to keep track of what type of hydrangea you have is to make a note when you put it in the ground. You can keep the nursery tag, write it down in a garden journal, or start a Google doc. If the plant was already in place and this information is not available, all is not lost.
If the plant is dormant and you can’t look at the leaves and blooms or use a plant-identifying app like Seek to identify it, you can look at the growth and see if there are existing buds along the branches. If there are buds, then it’s a variety that blooms on old wood and shouldn’t be pruned now. If there are no buds on the branches, that indicates that it’s a type that blooms on new wood, so it can be pruned now.
Here is a video from our friend Carmen Johnston of Carmen Johnston Gardens and Bespoke Garden Plans showing some of the common hydrangeas in bloom and what time of year to prune them.
For more tips and tricks on growing hydrangea, check out our growing guide.
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