I know I've pinned this here before - Moss Graffiti. Just mix some moss collected elsewhere with yoghurt or buttermix in a blender and apply with a brush to a textured/porous wall like brick or concrete. Spray with a water mister if the weather is dry.
designer industrial planter boxesmade by industrial designer Drew Sinclair @ bangsboutique. Made from reclaimed Australian hardwood with steel frame and on castors for mobility. Made for creepers as a wind break or privacy wall / fence.