I usually do not plant anything during the summer because it is so hot here. Any plant purchases, such as hydrangeas, stay in the shade, in a place also protected from drying winds. The plants are mulched and watered when the top soil feels dry.

It is difficult to determine if your plant will recover because it will not be obvious until the plant shoots replacement leaves or stems. Since you have had a problem with the plants in a pot, I suggest you dig a hole in a shaded location, free of winds and place the plant -pot and all- there. Make sure the pot has draining holes at the bottom. Cover the sides of the pot with soil and put mulch on top. When the temperatures moderate, extract the shrub and pot. Discard/recycle the pot and plant the hydrangea where you want to place it long term. Water it as soon as the top soil feels dry or almost dry. Check the soil daily for two weeks and write down on a wall calendar a note indicating that you watered it on a given day. After two weeks, review the notes and determine how often you had to water it (every 2/3/4/5 days). Then make a habit to manually water 1 gallon of water on the same frequency. Or set the sprinkler or drip irrigation to do it for you. If the temperatures change by 10-15 degrees and stay there, manually test the soil again daily for two weeks and see if you need to water more/less often.

Sometimes when a plant dries out completely like that it can be hard to get the rootball wet again. I would put the pot inside a 5 gallon bucket and water well until the water runs through. Then leave the water in the bucket and let it sit overnight. And get them both out of the sun.

I've done in the past what sue is recommending, and it worked great. The shrub is doing well, but it was slow going at first. So be patient. Limelights are tough plants, so after soaking overnight, it should be fine.

I continued to water and placed it in a 5 gallon bucket partially filled with water and set it in dappled shade. All the branches I thought were dead are beginning to leaf out again. I'm keeping my eye on it and giving it extra attention.

That's great! Don't be tempted to feed it. There is enough fertilizer in the pot it came in.