Once you’ve found out when to prune hydrangeas, it is also vital that you know how to prune hydrangeas and when to deadhead hydrangeas. ‘Pruning can improve the plant’s vigor; prune ones that bloom on old growth – lacecap, mophead, and oakleaf – after flowering, and in spring or fall for ones that bloom on new growth – paniculata and arborescens,’ explains garden expert Leigh Clapp.

Should I cut back hydrangeas in the fall

Whether you should cut back hydrangeas in fall, depends on the variety and when they bloom. Varieties that bloom on the previous year’s growth – also known as old wood hydrangeas – should never be cut back in fall as this will significantly reduce the number of blooms your hydrangeas will produce the following year. In fact, it could cause your hydrangea to fail completely. On the other hand, you should prune new wood hydrangeas in the fall before they start growing the branches that will produce the flowers. Regardless of which style of hydrangeas you are pruning, it is important that you approach with caution. ‘Wear gloves when pruning as contact with the foliage can cause skin allergies, and all parts can cause stomach upset if ingested,’ says garden expert Leigh Clapp. 

Cut back new wood hydrangeas in the fall

As their name suggests, new wood hydrangeas produce flowers on the new growth. These new stems grow each spring and, as such, mean that fall is the perfect time to prune new wood hydrangeas. New wood hydrangeas that you should cut back in the fall include:

Panicle hydrangeasSmooth hydrangeas

Whether you need to prune your hydrangeas in the fall or not, they will still need some TLC before the winter weather descends, learn how to winterize hydrangeas to make sure they make it through the coldest months of the year.

How do I know if my hydrangea blooms on old or new wood?

Wondering why hydrangeas aren’t blooming can be frustrating for any home gardener. You can find out if your hydrangea blooms on old or new wood by looking at the branches. If there are buds on the branch in the fall, then your hydrangea blooms on old wood and therefore should not be cut back in the fall. If there are no buds in sight after August 1, then you can cut them back any time from fall through to spring.