Provide shade and wait for them to recover. Keep plenty of moisture in the soil. Al

Thanks calistoga. How long should it normally take before they start perking up? Is it possible that too much of the root system was lost (I don't know how extensive the root system for a plant of that size should be ... seemed pretty small)?

Moving any plant in August causes considerable stress. Sounds like your hydrangeas are suffering from transplant shock, which is to be entirely expected at this time of year. As noted above, watering is critical (long deep soakings as often as necessary) and the shade won't hurt either.

It is possible not all the root system was saved but this is not uncommon either and many plants recover from this disturbance relatively well. If you keep providing the necessary TLC, you should see improvement in a week or two.

Folks - thanks very much for the information. I'm pretty sure one of the hydrangeas is dead; all the color is gone from the blossoms and it just looks completely wilted. It rained all day today, which must be good for the others. Will keep my fingers crossed.

I think your hydrangeas will survive. Endless Summer is a tough plant at my zone 5 garden. It can take a couple weeks for the wiltness to go away and maybe longer if the temp is hot. Just give it sufficient water and keep it from direct sun for as much as you can (but do not over water it), they should be fine.

My landscaper a couple years ago dug out my mature ES in the middle of a hot summer due to back patio repair. He did not replanted for a few days. Took a few weeks for the plants to recover but they were fine eventually.

The only thing I would strongly recommend in the future is to keep as much soil as you can when transplant, particularly with big plants. This will minimize the transplant shock.
Good luck,
Vivian

It may still recover but, yes, there is a chance that it may not. However, I have one hydrangea whose leaves dried out during August due to an undetected problem in my drip. The shrub was not too large and got shielded from sight by other large shrubs. When I discovered the problem in September, I continued giving it TLC. I kept the soil moist and well mulched but I did not fertilize as it was stressed. The plant did not leaf out that year but it did recover in Spring. So you see, there is a chance that yours can recover. Maintain the soil as evenly moist as possible, mulch it well, do not fertilize it until next year and see what happens. If it does not leaf out this season, wait until mid-May to see if it leafs out in 2014 instead.