Is moss a weed or a ground cover? It depends on your perspective. The sight of grass growing from a moss bed irritates many. It's also important to keep grass seed away from moss beds. It’s not easy to kill moss, but it is very easy to create a grass-growing moss bed.
Benefits of Moss
“Moss is a perfect seed bed, soft and moist,” says Jessica Budke, Ph.D., a bryologist doing post-doctoral research at the University of California, Davis. “That’s how grass gets started.”
Moss (minus the grass) offers at least nine benefits under the right circumstances.
- Given a little moisture, it is green.
- When it lacks moisture, it doesn’t die.
- It requires no digging.
- It likes to grow on compacted soil and even on rocks.
- It tolerates a wide pH and is well adapted to acid soil.
- It abhors mowers and rakes. (That's less work for the grower.)
- Deer don’t eat it.
- It loves the shade.
- It needs no fertilizer.
“Spring and fall are great for improving a moss bed,” says Dr. Budke. “In most places, moisture is more abundant, and temperatures are cool.”
Six steps to green up a mossy area:
Choose a shady spot. Low light and moss go together. While moss does not require shade, it gets less competition there from others plants--notably grass.
Remove grass and weeds. If grass and weeds are growing within existing moss beds, the simplest removal is gentle hand-picking. Do not rake! Dr. Budke says, “If grass is really thriving in the moss, it’s probably getting too much sun. If you want a better moss spread, increase the shade.”
Dial down the pH: Most mosses thrive in acidic conditions below 5.5 pH, though they can also grow in alkaline and neutral soil. Low pH discourages grass and many weeds, making it easier for moss to thrive. Garden centers supply soil acidifiers.
Spread new moss around the bare areas. There are three great techniques for doing this. Transplant moss patches is one effective way to integrate moss into the flora of your yard. “I mostly recommend transplanting patches of moss from other parts of the yard,” says Dr. Budke. “I’ve seen much practical success with that approach.” There's also the much discussed "moss milkshake, in which the plants are blended with water, beer, eggs, or buttermilk and then spread. According to Jessica Budke, method is not optimal, though interesting. You could also order live moss from a supplier and follow the instructions that accompany it.
Keep a rain barrel nearby. Moss does best with sky juice. “Tap water can be deleterious,” says Dr. Budke. “Most plants can filter unwanted minerals and substances through roots and a vascular system, but moss has neither of those. It absorbs everything directly through the cell walls.” Nonetheless, the key to happy moss is consistent moisture. If tap water is your only source, by all means, use it.
Clear away leaves. “Matted leaves make it too dark even for moss,” says Budke. “And as leaves decay, they encourage fungi, which discourage moss.”
One leaf removal method calls for tulle or bird netting spread over the moss garden. After the leaves fall, lift the net gently and carry them off. Alternatively, use a leaf blower. Remember, the successful moss garden is a rake-free zone.
Moss and planting supplies:
Moss Acres, Honesdale, PA
Mountain Moss, Pisgah Forest, North Carolina
The Magical World of Moss Gardening by Anne Martin, Timber Press, August 2015. Ms. Martin, also known as “Mossin’ Annie” is founder and president of Mountain Moss.
“Moss Growers Handbook” is a free PDF by Michael Fletcher offered through the British Bryological Society. It focuses on British species.
“The Secret Lives of Mosses: A Comprehensive Guide for the Garden” by Stephanie Stuber is written for professional gardeners as well as homeowners.
Gathering Moss: A Natural and Cultural History of Mosses by Robin Wall Kimmerer is an introspective, poetic and scientific look at the world of mosses. It won the prestigious John Burroughs Medal, which is administered by the Museum of Natural History.