I've seen them planted together in the same general vicinity but not next to each other. While they both enjoy acidic soil and a fair amount of irrigation, the blueberry loves/needs sun, whereas the hydrangea would prefer at least some afternoon shade. If you can reconcile that, I see no reason they can't be planted together.

Phoenix, where are you generally? If you are in more northern or cooler parts of the country, Hydrangea paniculata is fine in full sun. It needs shade in hotter parts of the country. IME Blueberries grown in less than full sun will grow in a rather rangy fashion and won't be as nice looking as ones grown in more sun, and also won't have as much fruit or as good color in autumn.

Thank you… I hadn't considered sunlight, and the area where I wanted to plant them is partially shady, so maybe I'll just go with the hydrangeas. (I am in zone 4.)

In zone 4, you will probably want to go for Hydrangea paniculata (such as Bobo, Quickfire or Limelight) or H. arborescens (such as Annabelle or Belle Anna.)

OK, thank you for your thoughts. I will look into these varieties.

There are a lot of different varieties of H. paniculata that range in size from perhaps 3 feet to 8 feet, and the bloom head shape varies, so you can choose a variety that suits your requirements. H. arborescens is about 4' tall and suckers, so will spread some.

Good to know.