If I were you, I would find a complimentary solid color that is found in the hexies. Don't try to match exactly. In the end, what you want is a simple frame of color to draw in the eyes of the viewer to show off the work that was given to you. You might even try, audition, a simple cream strip that is narrow and then a wider color that compliments the flowers.
Take your time and choose what feels good and right for this special piece of hand made quilt construction.