These look like they came from a garden center and possibly were forced into bloom. remove the spent flowers and give them time to settle in. I doubt more blooms will happen this year but next year they'll be lovely. Yes Tiffany is correct. Hydrangeas are thirsty shrubs. I've been dealing with a hedge of them on the north side of my house for over 16 years. late spring I prune them back to a healthy set of buds. Thats it plus water when rain has been scarce. They like rich loamy soil but manage to grow almost anywhere. No full sun please. Depending on the variety you have will tell you when to prune and good pruning is a must. By the fall all the dead flowers have been removed and I can nip and tuck the woody stems to keep the plant within size. Just don't take too much off. Good luck. Hydrangeas are a beautiful addition to any garden. BTW they make a good cut flower and some even dry nicely.
