Cor-ten steel planters patina from a gray steel color to a rich brown rust color. The planters will produce rust run-off from rain and watering that can stain concrete and other surfaces. To avoid rust stains on your concrete patio, place cor-ten planters along the unpaved patio border. Adding black river rock and pebbles around the planters will create a sleek outline and further accentuate the colors of the cor-ten steel.
