Do hydrangeas grow in Florida?

In broad terms, yes, hydrangea grow in Florida if they are planted in a spot that receives morning sun and afternoon shade.  I would suggest Endless Summer^® BloomStruck^® Hydrangea as it has great heat tolerance and is hardy to USDA Zone 9. I think the dark stems are gorgeous and really add to the ornamental beauty! Be sure they are protected from afternoon sun, perhaps siting the shrubs on the northern or eastern side of your home and ensuring you water them regularly during the season.