Climbing hydrangea (Hydrangea anomala ssp. petiolaris) is a woody, deciduous plant with vines that can climb 30 to 50 feet up trees, walls and steep banks or over rocks to form a dense mat. The vines show aerial roots when they grow along a wall. The plant is not considered invasive.
Sun and Soil
Climbing hydrangeas can tolerate shade and will grow on walls that face north. They like partial shade, although vines that get more sun produce more blossoms. They are especially recommended for shady, moist locations in temperate climates. In southern growing areas they need to be protected from the sun.
Plant climbing hydrangeas in soil that has a slightly acidic pH and contains plenty of humus. It should be moist but well drained.
Foliage and Flowers
Climbing hydrangeas bear dark green leaves two to four inches long in the shape of a heart. The leaves turn bright yellow in the fall.
The vines yield fragrant, irregularly-shaped white flowers, called "lace caps." The flowers have flat tops and are six to eight inches wide. They appear in June and last about three weeks. Climbing hydrangea produces fewer flowers than shrub varieties of the plant.
In the winter, the reddish-brown or cinnamon-colored bark sheds its outer layers in an attractive manner. Bare branches that are trained and pruned can be decorative.
Climbing hydrangeas are most often purchased in containers and planted. They are appropriate for USDA growing Zones 4 through 8.
A climbing hydrangea in a one-gallon pot will take up to three years to begin climbing and two more years to bloom. Plant from spring to fall at the same depth the plant occupied in the container; mulch the planting soil to retain moisture.
Climbing hydrangeas get more attractive as they age.
Aerial rootlets of the vines cling to all available surfaces. Climbing hydrangea can be pruned to make a shrub or used as a ground cover. The vines will cover fences, arbors or pergolas, climbing 30 to 50 feet if they are allowed to. They should not be allowed to climb houses with vinyl or shake siding. They may be usefully trained to climb the sides of brick or stone houses. Used as a ground cover, they can blanket up to 200 square feet.