I have a hydrangea that I started from a slip from one in my mother-in-law's yard about 5 years ago. It outgrew the pot it was in and I repotted it this spring. The ants are just loving this plant; I think I might have aphids.

I read somewhere that they need about 6 hours of sun a day to flower, but also that they need to be on the northern side of the house. I don't know about anyone else's property, but the north side of my yard is in the shade all day lol.