Your newly planted shrubs sound like they are doing fine, jen733. The first year is always stressful because all plants suffer from transplant shock. And of course, we are in the middle of the hot Texas summer. All the symptoms you describe, and more, are common until hydrangeas become established in your garden; it takes about 1-2 years for them to become established. Once that happens, the episodes will diminish but you will always have some due to the high temperatures and lack of moisture.
Blooms turn brown if exposed to too much sun or if the plant does not get enough moisture. If this happens, you can deadhead them or leave them until they naturally fall during winter. Protection from the sun can help prevent this problem. You can also minimize it by making sure that the soil is constantly moist. You can address one of the two causes religiously and, if you still have browning the next year then the problem is due to the other cause.
Lack of moisture can also cause hydrangea leaves to turn brown from the edges inwards. To address this problem, maintain about 4" of mulch about 6" past the drip line and maintain the soil as constantly moist as you can. You can use the finger method to help you out with this.
For the next two weeks, check the soil moisture early in the mornings daily by inserting a finger into the soil to a depth of 4". Determine if your finger feels dry, moist or wet. Do not water if it feels moist or wet. If it feels dry or almost dry, add 1 gallon of water a-n-d make a note on a wall calendar indicating that you watered on that day. After two weeks, determine how often you had to water (say every 3/4/5/etc days). Then set the sprinkler or drip irrigation to add 1 gallon of water on the same frequency (every 3/4/5/etc days). Water the soil (not the leaves) early in the morning to avoid fungal problems. Re-test using the finger method if the temperatures change by 10-15 degrees and stay there. Once the plant goes dormant, you can water once a week but make sure to water when winters are dry.
Wilting is a very common issue here starting May. Wilting in large-leafed plants occurs when they loose moisture faster through the leaves than they can absorb it through the roots. Most hydrangeas recover on their own by the next morning since wilting is actually a self defense mechanism that diminishes the leaf surface area in contact with the sun. But an extreme looking wilting episode can be bad and should be treated immediately by giving the plant ½ gallon of water. If the watering episode looks Ã¢â‚¬Å“normalÃ¢â‚¬