By Joel M. Lerner
Saturday, March 21, 2009
Perhaps you think moss grows like a weed because you see it everywhere -- on patios, garden furniture, lawns, the side of your house, on trees and in poor soil. It does, but only when it's happy.
When you do have ideal conditions, though, you can encourage it and create a moss garden to dramatic design effect.
These minute plants, which have a velvety look and feel, grow into thick coverings by catching dust and using their own decaying debris for a growth medium. During the prehistoric age, these carpets were the basis for all topsoil. As moss grew thicker, the bottoms of these thick masses formed rich compost, and in this soft, moist, rich environment ferns had their beginnings.
If moss is already doing well on your property, you will have to do little to make it the dominant ground cover. If you are going to experiment with mosses, it's best to stick with those that are in your back yard or from your part of the country.
One of the best authoritative texts on moss culture, history and identification is "Moss Gardening," by George Schenk. He says there are 1,200 species of moss native to North America and about 15,000 varieties worldwide.
"Gathering Moss: A Natural and Cultural History of Mosses," by Robin Wall Kimmerer, is a book that offers a mix of scientific information and personal essays.
The perfect environment for moss can run the gamut from sun to shade and acidic to alkaline, depending on the species. For many mosses in this region, shade and acidic conditions are helpful, and moisture is key to success.
A moss plant doesn't have a root system; it has a rhizoid that anchors the plant. It has no hollow tube or stalk; moisture climbs the stem through osmosis from one cell to another. It spreads through spores and by growing new stems and colonizing a patch of land, rock, brick or other material where it can thrive. A single colony that is centuries old can cover an entire property.
If the moss is doing better than your lawn, acidify with aluminum sulfate to rid the area of grass and weeds. Be very cautious when using aluminum sulfate, as it is a very acidic material that can burn moss if too much is used. Follow directions exactly.
Other methods of acidifying the soil to make it more hospitable for moss are wettable sulphur and iron sulfate. Wettable sulphur has a negative side. It kills good and bad funguses in the soil. So iron sulfate may be the safest method, used according to labeled instructions. It might take a little longer, and it will stain concrete or flagstone.
Instead of raking moss up and discarding it, try cutting pieces and planting them in other areas where they might look good. Sprinkle with water to help the plant establish. As with any ground cover, one of the greatest challenges to establishing moss is weeds. In the case of moss, getting rid of them is a painstaking process. Count on plucking seedlings from the moss on a regular basis to maintain a rich carpet-like appearance.
My experience at moss gardening began when I collected varieties growing in New Jersey in sandy soil and pastures fertilized with manure that supported mats of mosses that were two to three inches thick. There were red, yellow, tan and deep green. Some were shaggy looking, others were smooth with a sheared look. At the time, I didn't know the varieties because I was 8 years old.
The moss was transplanted to a piedmont clay soil. Three or four of the six plants that I took from their native sandy soil managed to adapt and thrive. They were dynamic and ever-changing. Some grew stalks that looked like microscopic flowers in a variety of hues, from gold to forest green. With rain, dew and temperate climate, the moss displayed its vibrant colors. When dry or cold, it turned brown and it was difficult to determine whether we had lost it. After a rainfall, it was evident which ones survived and which ones didn't.
A good time to plant moss in this region is early spring, with the onset of milder temperatures and rainfall. Schenk provides a recipe for a slurry method of moss propagation, where you prepare a moss mixture and apply it to the growing area: Place a pound of very finely particled, well-aged leaf mold or manure into a jar. Fill it two-thirds full with water. Shake well. Let it settle and pour off the water and floating debris, retaining the mud that remains in the bottom of the jar. In a blender, mix several pancake-size, moistened pieces of moss with a cup of mud from the jar. It should be about the same consistency as pancake batter. (Hint: Use screened soil to save the blades and motor of your blender.) Paint the material onto soil or unglazed bricks, and keep moist.
Oregon State University has extensive information regarding establishing moss on its Web site, http://bryophytes.science.oregonstate.edu/page30.htm. The site suggests variations on the two main methods: mixing a slurry, or transplanting moss fragments as you would a piece of sod, which is the process I used many years ago. You may want to use the methods together.
Here are some sources for cultivated mosses:
-- Sticks and Stones Farm, Newtown, Conn., 203-270-8820, http://www.sticksandstonesfarm.com/mossshop.htm.
-- Tripple Brook Farm, Southampton, Mass., 413-527-4626, http://www.tripplebrookfarm.com/tbf/man/prime/mosses.shtml.
-- Moss Acres, Honesdale, Pa., 866-438-6677, http://www.mossacres.com.
My landscape design background compels me to suggest that you complement your lush moss carpets with plants that offer year-round appeal. Here are some suggestions: primroses, crocuses, hellebores, oakleaf hydrangeas, native azaleas, evergreen sedges or a Japanese maple.
Joel M. Lerner is president of Environmental Design in Capitol View Park, Md. E-mail or contact him through his Web site, http://www.gardenlerner.com.