Hydrangeas are complicated in that the acid in the soil greatly effects their color. I would say as long as you are potting them and not planting them in the ground- you should be fine. Add a little lime juice (fresh not concentrate) to the soil if your color is not coming out right.
Also - it depends on your season. They do not do well in extreme temps. They need a nice warm client but not overly hot and not overly cold.