Most Hydrangeas produce great results but require little maintenance, and Hydrangea macrophylla 'Blue Danube' is no exception. When given space in a sunny or partially shady border or patio container, the hardy shrub will produce striking flowerheads in July and August. These blooms can grow to an impressive 20cm (8) in diameter, transforming cottage gardens and dominating any cut flower display. The papery petals are typically a blue-purple colour when the plant is grown in acidic soil, while an alkaline environment will result in a pink tone. Height: 1m (3'3). Spread: 1m (3'3).