Smooth Hydrangea 'Incrediball' (Hydrangea Arborescens) - Zone 3-9 Part Sun (south) to Full Sun (north) Heat tolerant. 4'-5' tall/wide. Prefers moist, well-drained soil-mulch well and don't let them dry out. Deciduous, cold-hardy bush blooms from summer to fall on new growth. Large, over 12" across, flowers open green, then mature to white before fading to green again. Very sturdy stems hold the blooms upright even if soaked with rain. Propagate by cuttings.