Panel (1) consists of a backing layer (5) e.g. of metal, plastic, concrete or rot-proof wood, covered with layer (2) of material that supports plant growth. The covering layer is made from lightweight stone fragments (3) e.g. expanded schist or clay held together by binding agent (4). The backing layer can be fixed to structure mechanically, by bolts/rivets, or chemically, by mortar/resin.