For light shade, it’s tough to beat Hydrangea macrophylla.
The shrub is easy to grow, needing little fussing beyond watering, occasional feeding, and light pruning once a year. Yet it pumps out big mophead flower clusters—in shades of pink, blue, and white—that can reach 10 or more inches across.
For really large clusters, grow H. arborescens ‘Incrediball’, which has 12-inch heads that open lime green, turn snowy white, then age to pale green on plants to 10 feet tall.
Grow garden hydrangea in zones 3b–9, 14–21; H1; ‘Incrediball’ in zones A3; 1–21.
More: Garden Hydrangea in the Sunset Plant Finder