Trouble With Driveway Moss

About Moss

• Mosses come in shades of yellow, green or brown and may grow in tufts or mats. Lichens and algae often thrive in the same types of locations as moss and may be found in combination with moss or mistaken for it. Moss presence usually peaks during the rainy, humid season. Mosses rarely damage the surface upon which they grow, although roofs may suffer from their presence. Instead, the biggest threat they pose on driveways and walkways is that they make the surface slippery.

Physical Removal

• Physical removal of the moss is key. Although physical removal will not necessarily prevent the moss from returning, it will make chemical treatments more effective. Use a pressure washer or strong spray of water from the hose as long as the water stream does not damage the pavement surface. Scrape as much of the moss off as possible. If physical removal adequately restores traction, chemical treatment may not be warranted.

Chemical Treatment

• Several chemical treatments work well to kill moss, though you must take care to make sure they do not stain driveway surfaces. Apply chemicals to impervious surfaces like driveways sparingly, as they can easily run off and harm plants or aquatic organisms. Products that contain potassium salts of fatty acids may offer some control without threatening nearby vegetation. Other moss-killing products include active ingredients like zinc chloride, zinc and copper sulfate, chlorine bleach and certain acids. Test chemicals, especially acids, on a small portion of the driveway to make sure that it will not harm the surface.

Additional Control Methods

• You can reduce the presence of moss by making the driveway environment less conducive to moss growth. Trim or thin out overhanging branches that cast shade on the driveway so that it receives more sunlight. Consider thinning out any adjacent vegetation to improve air circulation. Promptly remove fallen leaves, lawn clippings and other plant debris that covers the driveway. Check for water leaking from a hose, spigot or eave that could be providing moisture for moss development.