Should Hydrangeas Be Pruned in Autumn? A Gardener's Advice by Type
Panicle and smooth hydrangeas, the most common types in Latvian gardens, can be partly pruned in autumn to help them overwinter, while climbing hydrangeas should only be cut in spring. The advice comes from gardener Avita Jasliņa in the magazine “Praktiskais Latvietis”.
Gardeners in Latvia often wonder in autumn whether hydrangeas should be cut back before winter. Avita Jasliņa, writing in the magazine “Praktiskais Latvietis”, says it is each gardener's own choice, but for some types of hydrangea autumn pruning can help the plants get through winter.
Panicle hydrangeas
The author recommends doing the main shaping in spring, on a warm March day. The previous year's shoots are shortened, leaving only a couple of bud segments, from which 2–3 new flowering shoots grow. Dry and thin twigs are removed at the same time so the plant does not waste energy sustaining them.
In autumn, only the spent flower heads should be cut off. In her experience, this does not affect flowering the following year. Last year she left her panicle hydrangeas unpruned, and heavy snow broke many branches, while branches bent for a long time became deformed. Snow built up especially heavily on the dense flower heads.
Panicle hydrangeas grown as standard (tree-form) plants need particular care: before winter, check that the trunk has a stable support and lighten the crown by removing the flowers.
Smooth hydrangeas
Smooth hydrangeas (Hydrangea arborescens) form flowers at the tips of new shoots. In autumn the author shortens the young shoots and removes old, dry ones, then reviews the shrub again in spring and shortens shoots above the second or third pair of buds.
Climbing hydrangeas
Climbing hydrangeas keep their flowers over winter and are pruned only in spring, making room for new flower clusters.
Planting and an experiment
Container-grown plants can be planted until the ground freezes. The author also plans to test claims she heard from a grower: that a panicle hydrangea pruned earlier will bloom earlier, and that branches pruned at different times on one shrub will flower gradually, which in some varieties could produce the full range of colours at once.
