How to Prune Hydrangeas

Gardening Expert's Advice

Top gardening expert, Andrew Balfour, says that as the flowers of the common garden hydrangea (Hydrangea macrophylla) are borne in summer on the old wood, pruning should theoretically be carried out directly after flowering. Theoretically you could remove the old canes and dead-head the previous year's stems which only bore a single flower. However, he considers that in practice the pruning of hydrangeas is most successfully carried out in late winter when the leaves have dropped from the dormant plant.

How to Prune Hydrangeas?

If mid-winter is the time to prune hydrangeas, how do you do it? Andrew Balfour advises that if you look at a hydrangea at that time of the year you will see that there are different types of wood, according to age, on the bush.

You will see young, slender growths of the previous summer reaching up from the base of the plant and at the end of these stems there will be a large bud. This bud, in the next growing season, will produce a short shoot and then a flower.

Pruning Older Wood

There are also older shoots two seasons old. At the end of these stems there is a dead flower (if not removed by dead-heading), and a short distance down the stem will be found a cluster of large buds, usually four to six in number. These, if left, will each produce a flower the following summer. All that is needed is to prune the stem back to just above the cluster of buds.

Older, heavier stems of two or more seasons will also be found, carrying several dead flower heads, and these should be pruned back hard to the base of the plant to stimulate new and vigorous growth the following season.

How not to prune hydrangeas

Andrew Balfour concludes by saying that if the entire hydrangea is pruned back hard to the base, or if the stems are pruned to half their length, then it is quite possible that the flowering buds would be removed thus resulting in a poor show the following summer.