Hydrangea arborescens ‘Grandiflora’ (eastern North America)
Habit: Domed small to normal shrub, 1.5-(3) m tall and wide; often arching to the ground due to the weight of the flowers, slow-growing.
Flowers: Initially greenish white flower balls, then persistent pure white, end of June to August; no fruits.
Leaves: Ovoid, lively green, early shoots at end of April, no autumn colours.
Demands: Light shade to semi-shade, tolerates even deeper shade, cool, moderately frost hardy.
Soil: Fresh to moist, acidic to neutral, humic substrates; nutritious; always water in droughts or hot spells.
Note: Can be treated like perennial or semi-shrub, i.e. cut back to the ground in early spring each year. This leads to greater flower production with larger flower balls.
Hardiness: Zone 5a