I remember when I first saw Emerald Starburst in Geo Doorakian's garden, as a seeding. In a pot. I went to visit and he was working in the fields. ES was in a pot just behind the driveway head, kinda beside/behind me as I was waving to him.
He grinned, ear to ear and said take a look around, coyly....
I knew something was up but I was not expecting what I saw when I turned around and saw nothing but green!
The petals were turned back more than your pic so the green really showed.
Alas it and MALACHITE PRISM were not hardy here. Lost them both the first year.