I do use fusible Wonder Under when I do raw edge applique. I stitch about 1/8 to 1/16 inside the edge of all the pieces. This works best for me with batiks because they fray less than regular cotton. Your vine edges will get little fuzzy edges after a few washes. If you don't mind the fuzzy edges than I would say go for it. Your quilt top is beautiful and you've worked so hard already, a turned edge would be nice. It's your quilt so do what feels right to you.