On many of my cardigans I use a hemmed button band. I started doing these because I felt that the two layers were a sturdier fabric to sew buttons onto. But there are other benefits of a hemmed button band. They can be worked with the sweater, less finishing, you do not have to pick up stitches after you finish the sweater to work the button band. While working you can change skeins on the button band end of the cardigan then you do not have weave in those ends. You can use them to seam the button band or just tuck them in between the layers. Then when you are sewing on the buttons, those ends do not have to be woven in, they can be tucked in between the layers. Thus the beauty of a hemmed button band!
As mentioned above you can use your loose ends to sew the button band. When I have done this I start the seam where the loose ends are and work out from there going one direction with one and the opposite direction with the other. Of course you can cut a strand of yarn that is a little bit longer than the length of the button band and use it to sew the button band.
First you fold the button band along the twisted stitch (the first twisted stitch on the WS) that is in the middle of the purl stitches. You can see the the column of knit stitches (these are the purl stitches that are worked at the beginning of the button band on the RS). Next to that column is the second twisted stitch (on the WS). Then you have the knit stitches (these are the first set of purl stitches in the button band from the RS).
Next as shown in the picture I thread the tapestry needle through the outside leg of the first knit stitch then through the last stitch in the button band. You repeat this over the button band. How often I do a stitch depends on the weight of the yarn. If it is fingering weight I usually stitch every third knit stitch, if it is a worsted weight I usually stitch every other knit stitch.
When I get to the end I knot the yarn by making a stitch and threading the tapestry needle through the loop before the stitch is pulled tight. I usually do this a couple of times.
Then I thread the needle in between the layers for about an inch and pull the yarn through the layers.
Then you pull the yarn slightly and cut the end. Easy as pie and no weaving in loose ends!!