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

Japanese hydrangea vine · Hydrangea hydrangeoides 'Quelpartensis'
Grow in moist but well-drained, humus rich soil, in sun or partial shade with shelter from cold, drying winds and from late frosts, which may damage young leaf and bud growth. See climbing hydrangea cultivation for detailed advice
Consistently moist root zone, add extra water during warm dry weather