Moss Between Pavers
Getting rid of a persistent pain
I have a driveway surfaced with concrete pavers. The joints are filled with sand, but I can't seem to prevent moss from growing in them. Spraying weed killer didn't work. How do I get rid of the moss and how do I keep it away?
— Joseph, Pelham Manor, NY
Roger Cook replies: There are lots of people who pay to have moss added to their landscaping to make it look old, but moss on walks, decks, and driveways is unsightly as well as slippery.
Moss loves dampness and shade, so anything you can do to eliminate these conditions will tend to discourage it. Prune overhanging trees and shrubs to let more sunlight in, and adjust your sprinklers so they don't splash on the driveway.
Moss that's already taken hold can be removed from small areas with a stiff-bristle brush — since it has no roots, it comes up easily. Sometimes we scrub the area with a solution of
10 to 20 percent bleach to further discourage moss from growing back. But be sure to test this on a small area first, in case the bleach discolors the pavers.
If moss affects a large area, I blast it off with a pressure washer. Again, experiment on a small area first; a pressure washer used improperly can do a surprising amount of damage. Be sure to spray at a low angle across the joints, rather than straight down into them. Some people use different types of moss-killing herbicides, but I would rather see you take care of the problem mechanically than by adding more chemicals to the environment. By the way, never, ever, put an herbicide into a pressure-washer.