Installing Sedge Lawns as an Alternative to Turfgrass Lawns
Notes from Jenny Wiedower’s presentation on ARMN Chapter meeting, March 22, 2018
Disadvantages of turf grass
“Recent satellite photographs have shown that lawns (residential and commercial sites, golf courses, etc.) now occupy 45.6 million acres (which is 3 times the size of New Jersey) or 23% of urbanized land. This makes the American lawn the largest irrigated crop in the United States in terms of surface area, taking up more space than corn. Lawn irrigation on the east coast of the United States accounts for 30% of water use; on the west coast water used for irrigation is 60% of available water. The turf grasses that are most commonly used in this country are very shallow-rooted; therefore, the soil is not opened up and rainwater has no place to go, but to run off, and is thus lost to the system. According to the National Audubon Society an estimated 70 million pounds of pesticides are applied to lawns each year. This amount is ten times more per acre than is applied to agricultural crops. When it rains these toxic chemicals are carried away from the lawn and end up in our streams and waterways where fish and other aquatic life are at risk of mortality or morbidity. According to the Environmental Protection Agency, 40-60% of fertilizer applied to lawns ends up in surface and groundwater, contaminating them with excess nutrients. These excess nutrients lead to algal blooms, low dissolved oxygen, and impaired ecological health in our rivers, lakes, ponds, and coastal waters. Moreover, lawn fertilizers give off nitrous oxide – a greenhouse gas 300 times more potent than carbon dioxide.”
The California Environmental Protection Agency estimated that operating a commercial leaf blower for one hour would emit more pollution than driving a 2016 Toyota Camry for about 1,100 miles. http://www.mcclatchydc.com/news/nation-world/national/article174020786.html.
Gas-powered lawn and garden equipment is known to emit high levels of toxic and carcinogenic pollutants. Those emissions have been linked to stroke, respiratory illness and anxiety. https://www3.epa.gov/ttn/chief/conference/ei21/session10/banks_pres.pdf.
This equipment is also a source of environmental noise pollution: https://www.apha.org/policies-and-advocacy/public-health-policy-statements/policy-database/2014/07/16/12/50/environmental-noise-pollution-control.
Benefits of native lawns (vs. nonnative)
- Once established, native grasses are less susceptible to damage from pests and pathogens because they have evolved defenses against local fungi, bacteria, and insect herbivory.
- They require a fraction of the water use of traditional turf grasses, like bermudagrass, because they are adapted to the local water and weather regime.
- Many species that have been selected for native lawns are short and slow growing and require mowing as little as once or twice per year, or not at all if you like the wavy ornamental look.
- When it comes to weeds and overall appearances, many native grass mixes have consistently shown to develop twice the leaf density of traditional bermudagrass and allow significantly fewer weeds to creep in.
- The deeper roots of indigenous plants and trees help the soil to absorb water more effectively … you get more penetration of water and more filtration of runoff.
- Grass-like, triangular stem, hardy perennial
- Many varieties native to Virginia
- Work in dry shade or wet soil
- Resist deer browsing
- Excel as filler / ground cover
- In-leaf from late winter to late fall
- Caterpillars love them: Native sedges serve as host plants for 36 species of caterpillars.
Sources: Native Plants for Northern Virginia, pp. 19, 43; and Native Plants for Conservation, Restoration and Landscaping – Native Plant Finder
Pennsylvania Sedge is good lawn alternative.
Removing the existing vegetation will be the first step to eliminate competition and establish the new transplants.
If you have a traditional lawn of dense sod you may be able to remove it, in rolls, with a sod cutter. If the grass is not thick enough for sod it should be tilled into the soil with a rototiller, repeating every couple of days for a week to ensure the tilled vegetation does not set root and regrow.
The most ecological solution, however, is to smother the lawn underneath a plastic or biodegradable layer, retaining soil structure and adding compost as the vegetation decomposes underneath. To smother, begin in the spring by saturating the existing lawn with water, then cover with 20 layers of newspaper and approximately six to eight inches of fine mulch. Leave this cover for about three to four months then plant directly on top of it in the fall.
Alternately, you could cover the existing lawn with a black or clear plastic and seal around the edges with dirt. Over the summer, a greenhouse effect will cook the vegetation, the seed bank, and many pathogens that may be in the soil. Both of these smothering methods will add organic material to the soil and require less amendments than a full sod removal.