When I posted Findley, I promised that I would soon put up a tutorial for adding a ruffle to the back of a pair of bloomers, and so promise kept! Adding a ruffle is quite simple. The first requirement is picking the correct pattern. Many bloomer patterns eliminate the side seams and only have the middle crotch seam.
Here is a pattern without side seams.
This is fine from a pattern perspective, but doesn't work with adding a ruffle. So, the first requirement is using a pattern that has separate front and back pieces for the pattern.
Next, sew the center back seam so you are sewing the back right side to the back left side. This may not be the order given in the pattern directions. Once the left and right back pieces are seamed together, measure the width across the widest part above the crotch.
Double this number to get the length of the strip needed for your ruffle. The width of the strip can be whatever you would like. I made mine 2 inches wide, but you could make it wider or narrower depending on your preferences. Making 2 narrow ruffles would be adorable. Narrow hem the 2 long sides of the ruffle.
I used this tutorial. Run 2 long sets of basting stitches down the middle of the ruffle, 1/4 of an inch apart.
Pull up the basting stitches, leaving an inch to a half inch at each end ungathered. Pin the gathered ruffle across the widest part of the back bloomers above the crotch, or if adding 2 ruffles, slightly above and below the widest part, placing the short ends of the ruffle within the side seam allowances. Stitch the ruffle in place right down the center. Sew the back and front to each other at the side seams, catching the short ends of the ruffle in the seams. Finish the bloomers as per the pattern directions. That's it, a beautiful pair of ruffled bloomers!