Hydrangea petiolaris

Hydrangea petiolaris, a climbing hydrangea (syn: Hydrangea anomala subsp. petiolaris), is a species of flowering plant in the family Hydrangeaceae native to the woodlands of Japan, the Korean peninsula, and on Sakhalin island of easternmost Siberia in the Russian Far East. Hydrangea petiolaris is sometimes treated as a subspecies of the closely related Hydrangea anomala from China, Myanmar, and the Himalaya, as Hydrangea anomala subsp. petiolaris. The Hydrangea anomala species differs in being smaller (to ) and having flower corymbs up to 15 cm diameter. The common name Climbing hydrangea is applied to both species, or to species and subspecies. Description Hydrangea petiolaris is a vigorous woody climbing vine plant, growing to height and wide. It grows up trees and rock faces in its native Asian habitats, climbing by means of small aerial roots on the stems. The leaves are deciduous, ovate, 4–11 cm long and 3–8 cm broad, with a heart-shaped base, coarsely serrated margin and acute apex. The flowers are produced in flat corymbs 15–25 cm diameter in mid-summer; each corymb includes a small number of peripheral sterile white flowers 2.5–4.5 cm across, and numerous small, off-white fertile flowers 1–2 mm diameter. The fruit is a dry urn-shaped capsule 3–5 mm diameter containing several small winged seeds.