It is far easier to successfully tend to a plant in the ground than it is to do so for one in a container, especially young and rather large growing plants like hydrangeas. Locate an area in your garden that receives sun in the morning and then shade for most of the rest of the day, plant them and then pay close attention to watering throughout the summer. They should be fine.

Depending on the type of hydrangea, it might be wise to do some research on winter protection. Bigleaf hydrangeas, Hydrangea macrophylla, will often experience stem die back in winter in colder climates and that can impair or eliminate flowering unless protection from the cold is provided.