deciduous, woody vine that clings and climbs by twining and aerial rootlets along the stems, typically maturing over time to 30-40’ long. Horizontal lateral branching often extends several feet beyond supporting structures. Unsupported vines sometimes will grow in the form of a mounding shrub to 3-4’ tall, sprawling along the ground like a ground cover eventually covering an area of up to 200 square feet. This plant is native to wooded valleys, stream banks and mountain slopes in the Himalayas and China.
Opposite, simple, serrate, ovate, dark green leaves (to 4” long) have cordate bases. Non-showy yellow fall color. Fragrant white flowers in flat-topped clusters (to 8” wide) bloom in late spring to early summer (May-June). Each flower cluster consists of non-showy, creamy white to greenish-yellow fertile flowers in the center surrounded by showy white sterile flowers. Dried flower heads are reddish brown. Exfoliating bark on mature stems is also reddish brown and attractive in winter. Fruit ripens in September-October. Flattened clusters (corymbs 6-10” wide) of fragrant, white flowers in a lacecap configuration (small creamy white to greenish yellow fertile flowers in the center with a marginal ring of showy white sterile flowers) bloom in late spring to early summer (June-July). Fewer than 10 stamens per flower. Exfoliating, reddish brown bark of mature plants is attractive in winter. Once established, this vine can develop a somewhat bushy habit, with lateral branches growing out several feet from the support structure, thus giving the foliage a somewhat tiered effect.
Species plants are considered to be less ornamental than subspecies petiolaris, and accordingly are less frequently available in commerce. Subsp. petiolaris and cultivars there-under have become very popular landscape plants.
Subsp. petiolaris (formerly known as Hydrangea petiolaris) is native to eastern Siberia, Japan, China and South Korea. It differs from the species by its larger growth (matures to 60’ long), larger flower clusters (to 10” diameter), fewer showy sterile flowers per cluster, more than 10 stamens per flower, elliptic-ovate leaves (to 6” long) and better winter hardiness. Subspecies name is in reference to the long petioles of this plant.