I am new to gardening, but have a background in turf. I planted 3 twist and shout hydrangeas this spring and they are doing somewhat well, I just noticed that some on the leaves are fading to purple from the middle of the leaf to the end. It's not everywhere, just some here and there. I also noticed that this is happing on stems that are beginning to produce flowers. Also inside the plant some leaves are turning yellow-white (the vein also) and will fall off to the touch. This is happening to my Tardiva's and my limelight as well. Is this normal. I have noticed that jap beetles or some incsect have been chewing on the leaves last week, but I sprayed imidacloprid and cyfluthrin twice, 7 days apart. They get late morning sun to filterd evening sun. Any help would be greatly appreciated!

Thanks in advance.