There are soooooo many fabrics better than burlap. Burlap is just woven treebark, little or no strength, open weave, lotta weight for little return. You can use any thin cotton fabric such as muslin, or even light weight canvas.
If you have a local thrift store, go there and pick out two of the ugliest silk ties you can find and pick out the stitching. Great bow backing! Very unusual! Save any that have a hand painted tiger or hula dancer. I will send you an aged bowstave for that!