Cut a tapered scrap of fabric. The longer the scrap, the bigger the finished rose. Mine below is about 22" long X 2-1/2" wide at the widest end and tapers to 1" wide at the narrow end.
Press in half.
Run 1 or 2 lines of basting stitches joining the raw edges.
Knot off one end and pull the gathering stitches. Pull the gathering fairly tight.
Starting at the narrow end, roll the strip, keeping the raw edges even on the back.
Stop every couple of rolls and secure the roll layers by stitching through them. Continue rolling to the end of the gathered strip. Secure the layers and knot off your thread.
Repeat for as many flowers as you want to create. Attach to your garment with a circle of handstitches from the wrong side which grab the raw edges of the flower.
Stand back and admire your pretty (and easy!) flowers.