It should do fine in full sun in zone 5. The flowers emerge kelly green and then lighten to a lime green and then they dry a darker green. At this stage they are great for cutting and using in flower arrangements. In winter, outside, they will turn brown. In a vase they'll stay green for years. The plant is tall compared to Annabelle, about 5 feet, but stems are strong and it holds the blooms up without issue. The leaves are a very dark green and create good contrast w/ the flowers. In full disclosure, it is a plant that I developed, but in my opinion it is a beauty. If you look closely, the image below shows flowers of multiple ages.

Thank you so very much for your response. Very helpful. It’s gorgeous. Love the greens. Definitely going to give it a try!

Tim, what is your opinion on any of the arborescens cultivars in an area with periodic inundation? I have a fence row where I’d love to have the display of native hydrangea but wonder if they can handle some degree of sheet flow. I have other moisture loving native shrubs along the line and have been tempted to try a hydrangea. Drainage is good once the flow stops, it drains off generally within 24 hours. But the flow can last for more than a day, depending on the amount and duration of heavy rain. I know there is no guarantee, just wondering what the odds might be.