Bigleaf hydrangea Hydrangea 'Three Sisters Pastell' Blue-Pink-White - Hardy plantThree in one! The hydrangea 'Three sisters Pastell' (Hydrangea macrophylla) has blue, pink and white flowers. For colour and fragrance in your garden, patio or balcony. You can plant the hardy hydrangea all year round, provided temperatures have not dipped below freezing. The flowers bloom in the summer. Pruning is not necessary, unless the bush becomes too large. Plant the hydrangea in partial shade. Keep the soil moist and give it extra water during