Hydrangea macrophylla is a deciduous shrub that grows 3-6’ tall and wide. It features dark green leaves and large clusters of flowers which are either lace cap or mophead in structure. ‘Horwack’ (which is trademarked PISTACHIO) is a mophead cultivar known for its winter hardiness. It grows 2-3’ tall and blooms on old wood in late spring and, when deadheaded, again on new wood from summer into fall. Flowers open chartreuse and then turn scarlet red with a small blue eye. Plant in moist soil in part shade; attractive when massed in a shrub border or used as a specimen plant.