A ground cover in the form of a mulch, allowing air and moist to permeate, which includes a paper substrate originating from fibre-bearing pulp, preferably emanating from lignocellulosic material, which has been web-formed or sheet-formed, characterized in that the substrate has been impregnated with supercritical fluid, preferably CO2, alternatively a fluid under high pressure such as near supercritical conditions, wherein also one or more colorant(s) is (are) present in said fluid. Also a method for its manufacture and use thereof are disclosed.