Cold-Climate Hydrangea

A Hydrangea for Cold Climates

Smooth hydrangea (Hydrangea arborescens), also sometimes called hills of snow or snowball hydrangea, is an especially easy-growing type that's native to areas of North America. It has clusters of pure white flowers from midsummer into autumn; the older flowers often fade to green before they turn brown and dry.

Growing it

Grow smooth hydrangea in part shade and moist soil that's rich in organic matter. It's not very drought tolerant, especially if it's in a spot that gets afternoon sun -- so be sure to water it during dry spells and apply a 2- to 4-inch-deep layer of mulch on the soil. This extra-hardy hydrangea thrives in Zones 3-9.

Pruning it

Smooth hydrangea blooms on new growth, so if you need to prune it, the best time is in winter or early spring. Some gardeners cut it back to 6 or 8 inches tall every year to keep it dense and compact.

Standout Varieties

Hydrangea arborescens 'Annabelle' bears extra-large clusters of white flowers. It grows 5 feet tall.

Hydrangea arborescens 'White Dome' bears fluffy clusters of creamy-white flowers. It grows 6 feet tall and is hardy in Zones 4-9.