I think I would bind with the darkest green that you have in the square around the bear in the center of the Christmas runner. Or figure out how to make your binding one color on one side and another color on the other! That might be possible by sewing together two strips of different colors, each twice the width of your finished binding. Press in half, open out and press each color to the center (where the seam is.) Then apply each color to it's appropriate side and stitch down. I must have read this someplace because I'm not smart enough to have figured it out all on my own! LOL!!! Haven't done it, either.....
Please show us what you decide. I really like the idea of 2 sided things. Great fabric choices!
Sue