The Annabelle Hydrangea (Hydrangea arborescens 'Annabelle' is a popular, cold-hardy (USDA Zones 3-9) deciduous shrub known for massive, 8-12 inch white, snowball-like blooms in summer. Thriving in partial shade, it grows 3–5 feet tall, blooms on new wood, and requires moist, well-drained soil. 
Key Characteristics & Care
Sun/Shade Requirements: Best in partial shade (afternoon shade), but will tolerate full sun if provided with consistent, ample moisture.
Bloom Time: Produces lime-green buds in early summer that turn pure white for 6-8 weeks (June-August), often lasting into September.
Pruning: As they bloom on "new wood" (the current season's growth), they should be cut back to the ground in late winter or early spring.
Size: Generally reaches a height and spread of 3 to 5 feet.
Soil/Water: Prefers rich, moist, well-drained soil. They can droop if water is insufficient.
Uses: Excellent for shrub borders, mass planting, and as cut or dried flowers.