Hydrangeas are unpredictable. You expect a compact shrub with large leaves and clusters of even bigger bunches of flowers, and you get, what? Even when not in bloom, the climbing hydrangea--native to Japan and China--is both impressive and attractive. The leaves are heart-shaped, the stems reddish, and the blossoms creamy white. Climbing hydrangea flowers, like their shrub siblings, are actually groups of small blossoms, some of which are sterile, some of which are fertile.

Getting Familiar with Climbing Hydrangeas

The true climbing hydrangea is Hydrangea anomala ssp. petiolaris. A look-alike cousin-in-law, Decumaria barbara, does well as a groundcover, but will not flower until it finds something to climb. Another look-alike, the elegant Schizophragma hydrangeoides, hails from Japan. All three have the same basic requirements--rich soil, good drainage, and indirect sunlight--and aerial roots.

Telling these three apart isn't as difficult as it might seem. H. petiolaris, which reaches as high as 80 feet, has the cinnamon-colored woody stems, five-inch flower clusters, and oval, finely toothed, and shiny dark green leaves. D. barbara, which can reach as high as 50 feet, has leaves about two to four inches long, branches about two feet long, and fragrant flowers. S. hydrangeoides, which reaches only about 30 to 40 feet, has 10-inch lace-cap flower heads and six-inch leaves.

Ideally suited for a number of roles, climbing hydrangeas and their look-alikes do well both as foundation plantings and as specimen plants. Most varieties, and there are about 100 all told, are fairly hardy and resist most pests and diseases. All require ample moisture and may exhibit leaf drop in dry conditions. Care should be taken in where these plants are allowed to climb, because the aerial roots will damage wooden walls.