Thank you! I value your info. on the limelight hydrangeas.

I note you say you're watering every morning - this might be causing a problem. The best way to water plants is to wait around 5 days, and then give them a really good soaking (say half hour of the hose trickling at the base, or at least a gallon poured slowly round the base, of each plant). The reason for that is you want the plant roots to go down into the soil to search for water by themselves, so any watering you do should be sufficient to soak the ground down to 4/8 inches, otherwise the roots sit at the top and wait for you to come along every day, and you end up with a surface rooted plant which will suffer as soon as its not watered.
Unless your plants are in a contained bed with no drainage, or in pots with no drainage, overwatering isn't an issue, it won't be possible to overwater. Suggest you give them a really good soak now, as its so hot, along the lines I've suggested, and then don't water for 5 or 6 days, but preferably not long enough for the plants to actually wilt, and then do it again. In the heat you've got, you may have to repeat the watering every 3 days, if the plants only went in recently, but when you do water, do it a lot. In other words, little and often is not the thing to do - less frequent and a lot is.
The reason you've been told not to feed these is because this particular variety, whilst liking good, rich soil, develops lax and floppy growth if fed too much. Presumably your landscaper feels the soil is rich enough on its own without your having to feed directly.
Nice plants these - I'm tempted to get one myself, lol!