Hydrangea arborescens 'Annabelle'
'Annabelle' is a bushy deciduous shrub with broadly-ovate, dark green leaves and very large, spherical heads of white flowers in summeer.
Plant in moist but well-drained soil in sun or partial shade. Will reach a height of 2.5m and a spread of 2.5m after 10-20 years. Might require supports as it 'flops' due to weight of flower heads.