Hydrangea anomala, the Japanese climbing-hydrangea, is a species of flowering plant in the family Hydrangeaceae native to the woodlands of the Himalaya, southern and central China and northern Myanmar.
It is a woody climbing plant, growing to height up trees or rock faces, climbing by means of small aerial roots on the stems. The leaves are deciduous, ovate, long and broad, with a heart-shaped base, coarsely serrated margin and acute apex. The flowers are produced in flat corymbs diameter in mid-summer; each corymb includes a small number of peripheral sterile white flowers across, and numerous small, creamy-white fertile flowers 1âÂÂ2 mm diameter. The fruit is a dry urn-shaped capsule 3âÂÂ5 mm diameter containing several small winged seeds.
The closely related Hydrangea petiolaris from eastern Siberia, Japan, and Korea, is sometimes treated as a subspecies of H. anomala; it differs in growing larger (to ) and flower corymbs up to diameter. The common name Climbing hydrangea is applied to both species.
Hydrangea anomala is grown as an ornamental plant. The subspecies H. anomala subsp. petiolaris has received the Royal Horticultural Society's Award of Garden Merit.
'Hydrangea' is derived from Greek and means 'water vessel', which is in reference to the shape of its seed capsules.
'Anomala' means 'anomalous' or 'unlike its fellows'.