Two to three times more blooms per season than the smooth hydrangeas it was trialed against, which is the whole reason this one exists. Hydrangea arborescens 'BAIful', sold as FlowerFull, grows 3 to 4 feet tall and 4 to 5 feet wide, hardy from Zone 3 through Zone 8 in full sun to part shade, and reaches full size in two or three seasons.
Rounded white flower heads open in early summer and keep coming into fall, covering the plant rather than arriving in a single flush. The stems are thick enough to carry them upright without staking.
The foliage holds up too. Smooth hydrangeas are prone to bacterial leaf spot in humid summers, and this one was selected for resistance to it, so the leaves stay dark green through the season instead of going spotted and ragged by August.
Smooth hydrangeas flower on new wood, so buds form in spring on the current year's growth and a hard winter cannot take the display. That is why they bloom reliably in Zone 3 where the bigleaf types will not, and soil pH does not affect the color. Cut back in late winter. It wants steady moisture and does best where the soil never dries out completely.