Give 'Haas Halo' smooth hydrangea rich soil plus consistent moisture in a soil that drains. It may require extra watering, but no standing water. Place it in full shade or afternoon shade in the deep south (zones 8 and 9), but full sun is okay farther north. Best flowering is with some sun.
Is this a pollinator plant? Yes! This smooth hydrangea is a lacecap so it has a cener of fertile florets that really attract the pollinators.