The Old Florentine Bargello Filler Stitch makes an excellent background stitch. It is quick to work up and is more effective in large areas rather than in small ones.
It is formed by alternating two short stitches (over two or three canvas threads), followed by two long stitches (over six or nine canvas threads).
When stitched in a variety of colors, it can be used alone to cover an entire Bargello needlepoint project.
[...] These clever borders use a variation of the Old Florentine Bargello Filler Stitch. [...]