Your poppies are gorgeous! You've gotten some great advice and I thought I'd add my two cents worth. I would do raw edge applique where you use matching thread on each piece stitching a 1/16 to 1/8 inside the pieces. I knot the thread ends and pull then to the back to be hidden in the quilt sandwich. The edges of the pieces will fray up to the stitching and add to the effect. Do your thread play accents before quilting too because the back will look neater.
When you quilt your piece, you can add the quilting where you want without trying to stitch through each piece to anchor it. That said, do what YOU think will look best, if you are going to frame it and not wash it , it won't matter.