Hydrangea quercifolia 'Sikes Dwarf' Native Hydrangea
The Morton Arboretum recommends native Sikes Dwarf Hydrangea for smaller gardens. I would add also for cozy corners or shady nooks of a large garden.
In addition to the other reasons we love native plants, this baby is disease and insect free.
They will thrive in moist, slightly acidic, well-drained soil. As with all these shade lovers, mulch really helps them survive our summers.
You may have to protect it a bit since it flowers on old wood and the flower buds can be damaged in extreme cold.
Prune after bloom like most hydrangeas.