Why You Should Never Prune Hydrangeas In Autumn
As autumn edges closer, many gardeners instinctively reach for their shears, eager to tidy borders and get everything looking neat before winter sets in. But when it comes to hydrangeas, cutting back at this time of year could be one of the biggest mistakes you make in the garden.
It might seem logical to prune before the frosts arrive, but certain hydrangeas are already busy preparing for next summer. By autumn, some varieties have set their flower buds for the following year. Snip now and you risk removing every single one of those buds, leaving you with a shrub that produces nothing but leaves come summer.
The Two Types of Hydrangeas
Let me introduce you to Marianne, an avid local gardener who knows her way around a pair of secateurs. She explains that hydrangeas fall into two main categories: those that bloom on old wood and those that bloom on new wood. The difference is crucial if you want to see flowers rather than bare stems.
Why Old Wood Hydrangeas Should Not Be Pruned in Autumn
Marianne puts it plainly: mophead and lacecap hydrangeas, which are the pink, blue, or purple types that so many of us adore, bloom on old wood. Their buds start forming in the autumn ready for the following summer. If you prune them in autumn, winter, or spring, you remove every single bud that has been carefully set. The result? A summer of leafy disappointment with no colourful blooms in sight.
Old wood hydrangeas form buds on mature stems immediately after flowering and those buds sit there until the following year. That is why they should only be trimmed lightly in June or July, and only if the shrub has outgrown its space. Deadheading, on the other hand—removing spent flowers or dead stems—can be done any time of year without fear.
Can You Prune New Wood Hydrangeas in Autumn?
New wood hydrangeas are a different story. These include PeeGee and Annabelle varieties, which are usually white. They don’t set buds until the following growing season, so they can be pruned in autumn without jeopardising next year’s display. In fact, they bloom on fresh, green stems that grow in spring and summer, making them much more forgiving.
How to Work Out Which Type You Have
If you are unsure whether you have old wood or new wood hydrangeas, the easiest clue is their flowering season. New wood hydrangeas are probably still blooming now, since they flower in late summer and often keep going into autumn. Old wood hydrangeas, on the other hand, flower in late spring or early summer, and their buds are already sitting on woody stems waiting for the next season.
New wood stems tend to be greener and faster growing, while old wood stems are woody, mature, and slower to develop. If you’re still uncertain, the safest option is to avoid pruning altogether and take a sample to your local garden centre for identification..
To Conclude
The single most important step to successful hydrangea care is knowing which type you have. Prune an old wood hydrangea at the wrong time and you’ll be left flowerless for a year. Prune a new wood hydrangea and you’ll be rewarded with fresh blooms on next season’s growth.
So put down those shears for now and let your hydrangeas do their thing. A little patience in autumn will pay off handsomely in summer with those big, beautiful blooms that make hydrangeas such beloved garden favourites.
