I have some serratas in pretty much full sun and they are fine. But, full sun at the edge of the tall trees, in the PNW is not the same as full sun in the lower states. I have Hydrangea Serrata Beni Gaku, Serrata Preziosa, Preciosa and Serrata Beni. The Preziosa was first seen in a garden that faced west, on a bluff facing Puget Sound in full sun. It was huge at least 7x8 feet and beautiful. It was the inspiration for my trying the serratas in my garden. They do get supplemental summer water and have great drainage, being at the top of a hill in the garden. I love the serratas, smaller bushes, long bloom time and fabulous fall color. They are also easy to propagate.

Beni Gaku

Beni Gaku

Serrata Preziosa, Preciosa

Same plant as above - will show different colored blossoms at one time