How and When to Prune Hydrangeas
Pruning tips for regular (Mophead) hydrangeas by Peter Worsp
Filmed and produced by Pippa Marffy.
Summary of Winter Pruning Tips
Take a look at each of your flower stems and you'll see a series of buds. The bigger, juicy red buds are flower buds that set at the end of the summer just been, these will be ready to flower next season. Look a bit closer and further down the stem and you'll see smaller buds/nodules - these are leaf buds.
If you were to cut down to the leaf buds, you'd be cutting off all the flower buds and you wouldn't get any flowers in the next season. So only prune down to the last pair (or second to last pair) of big, healthy flower buds. A clean cut, on an outward facing angle is best.
Each year choose some stems to cut right back so that you crate some lower branches. Over the years your hydrangea will stay a good compact size.
Thin out old woody branches each year to encourage good airflow between branches and give the hydrangea a chance to regenerate (like roses, you can thin up to a third of the branches out).
If you want to bring the size of your hydrangea right back, but still want it to flower next summer, then prune it much earlier - in January or as soon as the first flowers are going over.
You can prune right down to the old wood (silvery grey wood). Pruning in the summer gives the hydrangeas a chance to set new buds whilst the weather is still warm and before it goes to sleep for the winter. These buds will follow the following summer.