>> I'm considering burlap, canvas, upholstery fabric, 1/4" door skins,
Maybe whatever remnants the fabric store has marked 'way down? You would eventually get a layered "patchwork quilt" effect.
Or pages torn from last year's seed and plant catalogs. Bakers Creek and Somebody-and-Perkins Roses have such gorgeous photos that I think of them as "Gardening Pornography".
