I have a First Edition Berry White Hydrangea. It’s new and was planted last fall and has beautiful blooms. But it keeps losing leaves. They turn…sort of a very dark yellow…but more brown, really and fall off. It have it on a drip system so I can adjust how much water it gets. I live in Zone 7 and it’s over 100 each day right now, so I am giving the plants on my drip about 20 mins. of water a day. Not sure what to do? It is getting too much or note enough water?
The discolored leaves are a sign of stress from the heat. And, the white patio and light colored rocks are helping to reflect the heat back to the hydrangea. You could transplant it to a container and then move it to a place with afternoon shade when hot spells settle in. As the extra watering might be leaching out the nutrients, be certain to fertilize in the spring.