Yes, you will need to stitch the edges. Steam a Seam will lift off and the fabric edges will fray in the wash. Here's a trick to keep your appliques from being too stiff. Apply Steam a Seam to your fabric but don't fuse yet with the iron, trace and cut out applique shape. Then trace another line on the Steam a Seam about a half inch in from the edge. Cut away the center part of the webbing so it looks like a window template on the back of your fabric. You'll still be able to fuse it down, but the stiffness will only be around the edges. A lot more comfortable on kid's clothing. Have fun.