its possible there is too much nitrogen in the soil. too much nitrogen will create very vibrant leafs but little to no bloom, also it can burn edges. put some mulch around the stems, that sucks up the nitrogen. also they dont like a lot of sun. morning sun, and lightly shaded for the remainder of the day. i water mine twice a week, with bonemeal, mulch. cut the leaves that are dead or dying. its possible bugs and or cats nibbling on them too. good luck.

I would try straightening some of the curled foliage to see if you have some common pests called Hydrangea Leaftier or Hydrangea Leaf Curler insects. They are common in the spring. The curling of hydrangea leaves could be caused by one of them. The hydrangea leaftier larva binds two or as many as four leaves together with strands of silk into a cup form and then feeds and rests between them. Pulling apart the leaves will reveal a half-inch-long slender green caterpillar with a black head. The leaf roller insect also causes similar damage, but rolls only one leaf, then feeds and rests within the rolled leaf. Both insects cause unsightly damage, but won’t harm the shrubs. When you see the damage, open the leaves to inspect the contents and squish the buds that you find. If this rates a 1,000 in your EEEEECK Scale, you can also remove the infested leaves (cut the petiole string that attaches the leaf to the stem) and squash the caterpillars. Clean up the ground below the shrubs, too, because the caterpillars drop to the ground and pupate in the summer and emerge as adult moths. This is a problem that can get worse as the moths may return to where they were born to reproduce; if so, the number of infected leaves gets larger (in numbers) with time. Expect some fall leaf color changes now that dormancy approaches. Water if a finger inserted into the soil at a depth of 4-6" feels dry or almost dry; skip watering if the soil feels wet/soggy. Use enough water when watering to moisten the soil down at a depth of 8". Mulching (3-4" past the drip line) can help minimize soil moisture loss. Feel free to deadhead spent flowers at any time but that is not required.

luis's suggestions make the most sense. That is evidence of some sort of insect infestation, maybe not current. Excess nitrogen will not cause that symptom although it can prevent flowering. And mulch does not "suck up nitrogen" either :-)

I was going to say the same thing as Luis did - uncurl the leaves and I bet you that some insects are hiding underneath! Good luck!!!

Based on the information you provided, it is possible that the hydrangea is experiencing stress due to overwatering or underwatering. Watering twice a day may be too much, especially if the soil is not well-draining and retains moisture for an extended period. On the other hand, if the soil is drying out quickly due to the drought in your area, then the plant may need more frequent watering.

To determine whether the plant is receiving the right amount of water, you can check the soil moisture level by sticking your finger about an inch deep into the soil. If it feels dry, then it's time to water the plant. If the soil feels moist, then hold off on watering for a day or two.

Regarding the fallen leaves, it's unlikely that they will grow back this season, but the plant should produce new leaves next spring.

I hope this helps! Let me know if you have any further questions.