I digress; getting back to the purpose of this post, which is how to prune hydrangeas. Knowing how to prune hydrangeas is key to growing beautiful hydrangeas. The first step in pruning is knowing whether your hydrangea blooms on old growth or new growth. Hydrangeas that bloom on old growth should only be pruned after they bloom. Hydrangeas that bloom on new growth should be pruned before they wake up in spring or as they are going dormant in the fall. The exception to this is my favorite hydrangea, the Endless Summer hydrangea. This hydrangea blooms on both old and new growth.
Old growth bloomers, like the ones shown above, bloom in early summer and are done by midsummer. They then set buds for the following year in late summer and early fall. Prune these hydrangeas after they bloom. Also, remove any spindly or damaged stems at this time. Trim off just the old blooms as soon as they begin to fade. Do not prune this bush back to the ground. Doing this will remove the buds for next year’s blooms.