NEVERMIND!
I called a bunch of florists and they all said they wouldn't be available. So now I'm aiming for this bouquet:
It's Roses, Calla Lilies and Stephanotis. The Calla Lilies are a bit iffy as to whether or not we can get them, but if we can't, I'll substitute them with White Asiatic Lilies. I still want my hydrangeas, but I would be perfectly happy settling for this one.