I read that deadheading Oakleaf Hydrangeas might stimulate more bloom.
These formed secondary blossoms without encouragement.
Had I not deadheaded, I would never have seen the new blooms.
Dotty Plants Journal in hot, humid Southwest Georgia. We had a brief rain shower, just enough to raise the humidity. Temperature remains at 89 degrees, so it wasn't a cooling rain, but it did wet the ground a little. More rain may be on the way.