This product is a fast-acting moss, algae and lichen killer for use on lawns, roofs, patios, fences, bark mulch and driveways. This product will not stain concrete or other surfaces and a single application will control moss and algae for several months to one year. Convenient hose-end bottle is ready to spray. Just attach this bottle to your garden hose. Water automatically mixes with concentrate as you spray. Not for Sale in DC, HI