A new and distinct cultivar of Hydrangea macrophylla (Thunb.) named ‘BC7.12’ originated as a controlled cross between varieties. The cultivar ‘BC7.12’ can be blue or red depending on the acidity of the soil and the presence of aluminum. The variety ‘BC7.12’ has compact, attractive inflorescences with relatively large sepalous florets, attractive sepal pigmentation which resists fading, long lasting blooms which set flowers evenly, stems that branch easily and are strong, and good commercial characteristics. When grown without aluminum, the upper sides of the sepals of the sepalous florets are primarily R.H.S. 67 A (red-purple group) and the under sides of the sepals are R.H.S 68 A (red-purple group).
