I would expect them to "behave" as if they were originally planted for the first time.

So that means that hey may "fuss" a bit, the leaves may wilt a little, maybe wilt a lot in the worst of the summer months (so not much, if any, wilting now as temps are probably nowhere hot). The shrubs look like they are just awakening so that will help. Mild temps will help also. If you did not harm the roots then that will also help greatly too.

As for watering, use the finger method daily for 2-3 weeks to determine when to water: insert a finger to a depth of 4" into the ground and water if the soil feels dry or almost dry. Test the soil daily at about the same time of the day. When you water, make a note in a wall calendar. Then after 23 weeks, review your notes in the calendar. Calculate about how often you had to water (once every 2/3/4/5/etc days for example). Then give the plant water on that frequency. I am having trouble guessing how much root area you have but I would guess 1/2 to 1 gallon per plant (?) will be fine. If the temperatures/weather go up about 10-15 degrees and stay there, try using the finger method again to see if you need to tweak things. I would expect watering to be stable unless a rainy season starts or ends or summer arrives.

Maintain 2-4" of mulch year around so the water will not evaporate quickly.

Transplant shock may cause other "behaviors" like browning of leaves but hopefully not; feel free to post any problems that you notice.

Luis

I totally agree with Luis about watering. It's not a prescribed amount, but depends on soils, mulch, temperatures and amount of sun among other variables. You have to figure out what works to keep the soil moist, not saturated or dry. The finger method will let you know when your plants need water.

I transplanted several last year while they were dormant and they woke up just fine. In fact, they were clearly much happier in their new location and rewarded me come bloom time.

The thing to consider is the type of hydrangea. If these bloom on old wood like Macrophylla, you may have trimmed the existing buds during the transplant, and that would result in fewer blooms.

Otherwise, follow the advice already given for watering and expect a nice show come Summer.