How to Water Japanese climbing hydrangea?
Consistently moist root zone, add extra water during warm dry weather

Japanese climbing hydrangea · Hydrangea anomala
Grow in moist but well-drained soil rich in organic matter, and shelter from cold, drying winds. This species climbs using aerial roots and will need suitable support, especially when young. Mulch annually in spring. See climbing hydrangea cultivation for more detailed advice
Consistently moist root zone, add extra water during warm dry weather