sounds like reverse applique. when i made my fall leaf quilt i went for a walk in the woods and collected wonderful, beautiful leaves of all sorts. took them home and pressed them in a book. then used them to trace onto fusable and cut them out of batiks. if you want to needle turn that's simple too, trace the leaves, add a little turn under allowance and cut them out. I would trace them on the fabric with a white pencil, or chalk.
batiks are abundant in lots of shops and prices vary as much as shops do. batiks plus...batiks by design, ... bayside quilting, fabric.com, the cotton patch (in East Tawas, mi) are a few on line shops that have a pretty good variety of batiks. have fun!