As autumn approaches, many gardeners may be tempted to start pruning their plants, but cutting back hydrangeas during this season is a significant mistake. While it might seem natural to prepare plants for winter by trimming them, some hydrangeas have already developed their flower buds for the next year.
Pruning certain types of hydrangeas now could mean cutting off the buds that would have bloomed in the summer, leaving the plant bare with only its leaves to show. According to gardener Kelly Elko, understanding whether your hydrangea blooms on old wood or new wood is key to knowing the right time to prune.
Why You Shouldn’t Prune Old Wood Hydrangeas in Autumn
Elko explains that old wood hydrangeas, like Mophead and Lacecap varieties (usually pink, blue, or purple), start forming buds in the fall for next summer’s blooms. If you trim them in autumn, winter, or spring, you risk removing all the buds, leaving the plant flowerless in the summer.
Old wood hydrangeas produce flowers on woody stems that begin growing right after the current season’s blooms fade and remain on the plant until the following year. These hydrangeas should only be pruned in June or July if they have grown too large. Deadheading, or removing dead stems or flowers, is safe to do at any time of the year.
Can You Prune New Wood Hydrangeas in Autumn?
New wood hydrangeas are safer to prune in the fall since they haven’t formed their buds yet. Kelly advises that PeeGee and Annabelle hydrangeas, which typically produce white flowers, bloom on new wood. These can be pruned in the autumn and will still bloom on new stems the following summer.
How to Identify Old Wood vs. New Wood Hydrangeas
One way to determine whether your hydrangea blooms on old wood or new wood is by looking at its flowering pattern. New wood hydrangeas bloom later in the summer and may still be flowering into autumn. In contrast, old wood hydrangeas bloom earlier, usually in late spring or early summer.
New wood hydrangeas also tend to have buds on green stems, which grow faster than the woody stems of old wood varieties. If you’re still uncertain about the type of hydrangea you have, it’s best to avoid pruning or consult a local garden center for help in identifying the plant.
Knowing the type of hydrangea in your garden is essential for proper pruning. This ensures you avoid cutting at the wrong time and enjoy vibrant blooms next year.