Wondering when to prune your hydrangeas? The answer depends on what type of hydrangea you have.

The bigleaf hydrangea (Hydrangea macrophylla) should be pruned shortly after it flowers, as it flowers on old wood. Don't wait too late into fall to pruning that can stimulate tender new growth that might be killed during winter.

The climbing hydrangea (Hydrangea anomala ssp. petiolaris) should be pruned in early March, as needed to control it's height. This type can grow to 50 to 60 feet.

The smooth hydrangea (Hydrangea arborescens) should be pruned down hard to 1 foot in early March, as it grows on new wood. This species propagates itself by sending up many ground-level suckers, which may also be cut out. This shrub can become top-heavy if not pruned regularly.

The panicle hydrangea (Hydrangea paniculata) and its cultivars also flower on new wood but don’t require the drastic pruning of the smooth hydrangea. They will look best if one-third of the old growth is pruned back in late winter. If unpruned, these cultivars can reach 20 feet.

The oakleaf hydrangea (Hydrangea quercifolia) flowers on old wood also but is often left unpruned since its spreading habit is quite attractive. The huge, 12-inch flowers are quite ornamental and will lend a late-season interest to the autumn garden. If the terminal buds of this type are killed off during winter, the plant will not flower.

With all varieties, remember to remove any winter-damaged branches in early spring.

This information was supplied by the Chicago Botanic Garden.