Apparently the foliage is getting wet and this is causing a bad leaf spot infestation. Water the soil and never the leaves to minimize the chances of getting fungal issues on the leaves. To know when to water, inset a finger to a depth of 4" and water if the soil feels dry or almost dry.

If you water when the leaves are wilted, there is a danger that you are watering too much. The leaves will wilt/droop when they lose leaf moisture faster than the roots can absorb more water. The internal pressure differential causes the leaves to wilt then. Scenarios that trigger this condition: temperatures above 85F; too much sunlight (aim to give them dappled sun or morning sun until 10-11am; no afternoon or evening sun if possible); hot, drying winds; lack of water or lack of enough water; small root system (new plants) or disturbed roots due to transplants.

Wilted plants can be left alone if the soil is sufficiently moist (use the finger method to check); they will perk up at night on their own if the soil has sufficient soil moisture. In the hot summer months, I make a habit to visually use the finger method when I see wilting and I water immediately if the soil feels dry. If the soil is moist, I let them be and I re-check in the morning. Somewhere around 6-8am when I wake up, I see if any is still wilted. If so, they get water.

If you water just because they are wilting, you may be watering too much. That can cause leaf and bloom fungal problems (as seen in the picture) and-or root rot (if the soil remains soggy long enough). Watering twice a day can sometimes be done in well draining soils but try not to make a habit of it.

In the fall, discard all foliage and blooms in the trash as they will contain lots of fungal spores; do not put them in the compost pile. If you deadhead any blooms now, discard them in the tras too. You can also cut off the worst of the leaves but do not assume you will get new foliage quickly while in the middle of the summer (maybe in the fall or in spring).

Water the soil only, from now on instead. If using a sprinkler system, water around 6-8am so the leaves do not spend the night wet. Use clean sanitation practices (discard plant material in the trash if any falls down or is left in the fall; water the soil only; do not overwater; prune leaves so plants do not touch, something that can help increase air flow and reduce humidity, etc.) as best as you can to minimize spreading the fungal infection to other hydrangeas.

I dont have anything to add to Luis´ expert advice except my own experience with hydrangeas that wilted in the afternoon sun. I threw in the towel and moved them to partial shade. I couldnt keep up the watering and the ugliness of hydrangeas that wilted like clockwork in between 1 and 4 pm. I moved to all day partial shade or afternoon shade.

Twist and Shout was too big for us to move, so I gave it someone with a broad back and big arm muscles. What a relief to see the reminder of a poor choice gone!

The consolation: all the beautiful paniculata hydrangeas that bloom early and reliably.

PS it would help if you added your zone and biggest nearby city to your name.

People will be able to give you better advice when they know where you (and your plants) live.

Thanks for the info. I live just south of Columbus Ohio. The plants are on the North side of my home. I know they call for mourning sun and afternoon shade but I figured all shade except for a few hours in the evening would be fine. i definitely made watering mistakes especially getting the leaves wet and watering in the evening. My biggest question was if this was a fungal/disease issue or a Sun/watering issue? i do understand that the bad watering technique will cause fungal issues.

A fungal disease that is just about everywhere and spreads easily when the environment is humid.

Iḿ not clear if the plants are in hot direct afternoon sun, say, from 1-4 pm , and I dont understand what you mean by ¨evening.¨ 5-6 PM? IN my location the sun dips down below the trees by late August. Thereś garden spots that get 2 hours less direct sun than in June and July.