What look are you wanting to achieve? Right now it has a more modern look, adding any type of border may change that look. Since the dark green is spread over the quilt binding it in that color would give it a nice, clean finish. Personally I think that would be a good choice to finish the look it currently has. It is a beautiful quilt, green has so many special meanings in different cultures, but the constant theme is a long, healthy life. Excellent choice!