Over 15,000 species of moss grow on Earth. This simplest of plants is classified as a Bryophyte--a non-vascular land plant that does not produce flowers or seeds, and has rhizoids rather than roots. These mosses grow on rocks and the soil. The mosses which grow on trees and leaves are known as epiphytes, obtaining only support from the host, not nutrition.
What are the benefits of moss?
Moss is an excellent source of erosion control. Moss aids in soil moisture retention and, as a result, a greater concentration of nutrients. Moss is naturally aesthetic, providing maintenance-free beauty. Planted in the right location, this hardy organism reproduces quickly.
Where does moss grow best?
Before deciding to include moss in your garden design, think about where you see moss occurring naturally in Nature. Moss thrives in areas with little light, high levels of moisture, and somewhat acidic soil (pH 5.5). Temperatures do not affect moss growth, other than to slow it during the hottest, driest months of the year. Moss has the ability to dry out and remain dormant until the rains return; it seldom completely dies out. (Sphagnum moss is said to cover 1% of the Earth's surface.1) Check out your own property and see what moss already grows there.
Moss can be used to replace small areas of turfgrass that are compromised by adverse growing conditions, such as properties that are deeply wooded. Moss can also be used in shade gardens to complement other shade-loving plants. The ground beneath large shade trees such as maple, oak, ash, or tulip poplar is a perfect spot to replace turf-grass. Moss does not thrive under conifers.
Decisions, Decisions! Moss Lawn or Moss Garden?
Before you embark on tearing up your turf-grass or redesigning a shade garden, investigate the resources for obtaining the correct moss plants for the job. Also, one must consider the cost of the project. Mosses are sold by clumps in square foot lots, ranging from 5 square feet for $89 (USD) to 25 square feet for $119 (USD).2
- Fern Moss (Thuidium) is the moss of choice for areas which will receive foot traffic. It is low-growing and will tolerate some dappled or morning sunlight, but no direct afternoon sun. Color is medium green.
- Cushion Moss (Leucobryum) grows well in sandy soil and tolerates some partial sun. It does not tolerate foot traffic and is more suitable for planting beds. Color is light green with silver-white cast.
- Haircap Moss (Polytrichum) anchors to the soil with fibers that function like roots. Prefers medium shade and well-drained soil. Color is bright green and more upright than other moss types.
- Rock Cap Moss (Dicranum) is the moss you see growing in the wild on rocks and boulders. Needs full shade to thrive. Color is medium to dark green.
A possible alternative to purchasing moss is locating naturally-occurring moss to transplant. Most importantly, be sure you are not trespassing on private property, or violating state or federal laws regarding plant removal from public lands. Once you've established that, choose sites that have similar or identical environmental factors to your proposed site. Transplanting moss can be tricky, and you'll have better success if you take this into consideration. Remember, if you took the moss from a rock or boulder, it will not thrive if planted in soil, and vice versa.
If replacing a lawn or section of turf-grass, you must eliminate the grass before planting the moss; Glyphosate-containing herbicides such as Roundup®3 will kill the grass. For either lawn or planting bed, he ground must be free of existing plants, twigs, leaves, or other debris. Smooth the soil and tamp down slightly. If soil pH is higher than 5.5, lower it by adding either skimmed milk powder, powdered sulfur, or a commercial rhododendron fertilizer. Water lightly to dissolve the powder.
Planting or Transplanting the Moss
University of Vermont Extension recommends the following:
- Dig sods of moss at least the size of an outstretched hand, taking up plenty of soil to keep rhizoids intact.
- Press pieces of sod in place to make good contact with the soil.
- Water thoroughly.
- Water regularly during the first year, even into the winter months, and especially any time that the surface soil dries out.
- After the moss has established, avoid regular traffic for the first year to allow it to really take hold.
Hurry up and Wait!
To incorporate moss into your landscape will require patience. It may take several growing seasons for a moss lawn to fully fill in, or for boulders to be blanketed in green. But it will be worth it.
1 Michael McKee, Ohio State University. http://www.hcs.ohio-state.edu
2 Moss Acres. http://www.mossacres.com
3 University of Vermont Extension. http://www.ext.vt.edu
Photo forest moss: IvoShandor, used by permission of GNU Free Documentation License, Wikimedia