I should add that I have clay soil and the blooms do look normal and beautiful in the morning and evening. I just don’t remember them drooping so terribly during the day last year!

Hard to say what is going on. I have three macs that are also drooping, but I am sure it is because they were planted about three weeks ago and need a lot of water to sustain themselves in the summer heat. I also had to put more compose as the roots kept becoming exposed.

From your name, it looks like you live in CT. Contact UConn's Home and Garden Education Center. Send them the photos and ask them for advice. I am sure that they have hydrangea experts who can provide helpful info.

It's not a mystery. If they're okay morning and evening the issue is that transpiration during the day is not keeping up with water intake at the roots. Result : loss of turgidity. They're thirsty. Do what Eileen said.

Thank you all! I am so grateful for the experts on this forum. I will extend the time on the drip and supplement with a hose and see how they do! I was scared of overwatering them but it doesn’t seem to be the case!

Be careful if you are controlling watering by timing the drip system. Consider if a dense shrub of that size is receiving sufficient irrigation as type of soil, temperatures, etc etc. are factors to consider. Aim to water deeply if the soil feels dry at a depth of about 4 inches and provide sufficient gallons of water to moisten the soil at a depth of 8 inches (test only periodically after the water percolates). Here in Texas and with my drip pressure set up (consult with the landscape company/person that installed yours) 90 minutes of drip would yield only 1.5 gallons and may not be enough in some instances. Similarly, do not water every 2-3 days; instead, test the soil moisture very often -almost daily- at a depth of 4 inches and then water the soil deeply if dry. Ensure the soil remains mulched with 3-4 inches of organic mulch past the drip line all year long. Here in Texas where summers are very harsh with temperatures above 100F from June until October, wilting is unavoidable during the hottest parts of the summer days so you cannot prevent it but, you can keep the soil as evenly moist as possible as previously described so that, at night, your shrub will perk up on its own if it is sufficiently watered, mulched and given shade by 11am. Note: sun exposure by 3pm is not morning sun and is not always recommended near the summer as the leaves can sunscorch and blooms can brown out prematurely. To test for overwatering, consider inserting two fingers into the soil to a depth of 4 inches and retrieve some soil in between the fingers; then press on the soil and observe if water droplets are forming or not. Or follow the suggested guidelines mentioned earlier at a depth of 4 and 8 inches.