WordNet sense 1 (climbing shrub with adhesive aerial roots having opposite leaves and small white flowers in terminal cymes; Himalayas to Taiwan and Japan):

Schizophragma hydrangeoides

WordNet sense 2 (deciduous climber with aerial roots having large flat flower heads):

Hydrangea petiolaris

WordNet sense 3 (deciduous climber with aerial roots having white to creamy flowers in fairly flat heads):

Hydrangea anomala