Answer: Hydrangea paniculata 'Grandiflora', also known as Peegee hydrangea, is hardy to about zone 4. In order to make it happy in Utah, you should give it a growing bed rich in organic matter. Mix a few inches of compost into the soil to build up the organic matter content. You may also need to add a pound of powdered sulfur per 100 square feet if the pH is above about 7.5. It would prefer a shady location. Some morning sun is alright.
Good luck with your hydrangea!
Q&A Library Searching Tips