Looks like they are suffering from transplant shock. Very common on newly planted shrubs and expected when you plant new ones in the middle of the summer. If they get too much sunlight, the leaves in direct contact with the sun will turn all yellow, including the leaf veins. So, these guys look like went from a comfortable shady spot at Lowes to a more sunny and hot spot in your garden. Going forward, I suggest you transition them slowly into sunny areas: say, buy them in the summer, keep them in bright shade until summer temps have come down and plant them in the Fall.

When the big leaves on these guys started to loose moisture faster than the roots could absorb water, the leaves wilted. As this condition got more intense by not being used to the hot outside, the leaves dried out from the edges inwards and some sections now look brown. The wilted leaves should normally recover on their own if you keep the soil moist. Usually they recover either by nighttime or by the next morning. If they have not recovered then test the soil to see if it needs water. But keep a close eye on the soil moisture levels in the middle of the summer and water as often as needed.

Do not forget that pots get hot when hit by either morning or afternoon summer sun.

Completely dried out leaves can be cut off but I would leave the partially browned out ones. If it bugs you, you can squish the brown out parts so they are not so obvious. Dried out leaves will not recover but the shrub sometimes generates new ones either now, in the Fall or as late as Spring 2016.

Any location where they get morning sun until 11am or so (approximately) is probably ok. Locations that get some sun in the afternoon might work too but you have to "test" them to see and mid-July was probably a jolt to them. In the northern states, they can get full sun but, I still would not "introduce to the outside" in the middle of the summer. :o)

I had one hydrangea that lost all leaves due to watering issue (not potted but planted in the ground). This happened near the end of the growing season. I maintained the soil moist and well mulched. It looked worse than yours. While it did not produce new leaves that season, the roots were fine and made it leaf out in the Spring like nothing had happened.

Enjoy, the Mini Penny Hydrangeas. I almost got some myself at another store.

Thank you so much! I believe the Mini Penny are designed to do well in container pots since they are in the dwarf family.