Green Per Square Foot

Strategies for converting monocultures (turf lawns) to native plantings July 29th, 2014

Disadvantages of monocultures

The corporate lawn is a term used to describe large, traditionally mowed grass lawns common in association with corporate headquarters, office buildings, schools, governmental building complexes and shared open space in large residential developments. These areas are usually comprised of cool season, non‐native grasses that require frequent inputs of water and fertilizer as well as regular weekly mowing throughout the spring summer and fall. Periodic applications of herbicides, fungicides and insecticides may also occur. Such inputs may result in an unhealthy soil condition that will require further inputs in order to maintain the attractive green lawn. Conversion of these areas to local native plants such as native grasses, wildflowers, shrubs and vines will provide for healthier soils and greatly enhanced local ecological functioning.

Introduction to native plants

These native plants are adapted to local soil pH, nutrient levels, soil moisture and weather conditions so they do not require large chemical inputs in order to thrive. Wildflowers such as butterfly milkweed, horse mint, violets, goldenrods and asters also are well adapted to local native soil conditions. These plants evolved with native soil fungi, bacteria and invertebrates and help maintain a healthy soil ecosystem. No excess water or nutrients, that may degrade local surface and subsurface water quality, need to be applied to maintain these native plant populations.

Converting from turfgrass to native plant landscaping usually involves killing the turfgrass first. How you might kill the turfgrass is dependent largely on what species of grass it is.

Three Options to Kill or Remove Turfgrass

Physical Removal (Sod Cutter)

  1. Killing Turf-type tall fescue, fine fescues, and perennial ryegrass can be as simple and easy as cutting and removing the sod by renting a sod cutter. (Just make sure you cut below the crown of the grass plant.)
  2. Kentucky bluegrass, because it spreads by creeping roots (rhizomes) that grow below the lowest setting of the sod cutter knife, probably will not be killed adequately by sod removal. Bermudagrass will definitely not be killed by sod removal.

Smothering

  1. You can kill lawns by excluding all light. Cover your lawn area with newspapers and a layer of mulch (sheet composting) in the fall and in the spring it will be dead. Or you could lay down used construction materials like sheetrock or plywood. You can also use black plastic (solarization). Excluding all light is necessary.
  2. Technically, solarization is a method of soil sterilization using clear plastic, but a version, which might be called ‘light exclusion’ using black plastic, works for lawn removal. This method works best in areas with high summer temperatures, and should be done as spring is turning to summer. Cut the grass as short as possible and water well.  Cover with large rolls of sturdy black polyethylene held in place by rocks or metal stakes. Cover the area, making sure it is airtight with no holes. The plastic sheets allow the sun’s radiant energy to be trapped in the soil, heating the top 12 to 18 inches. When properly done, the top 6 inches of the soil will heat up to as high as 140°F, depending on the location.  Leave in place for about 4–8 weeks—depending on how hot the weather is–until grass is dead.
  3. Smothering will not work on Bermudagrass.

Herbicide (Glyphosate)

  1. Glyphosate is effective on all types of turfgrass, but the grass needs to be actively green and growing for the herbicide to work. This is the only method we know of to successfully remove Bermudagrass. You can spray one day and usually can proceed to the next step of landscaping within about 10-20 days.
  2. When the grass is dead you could dig holes and plant directly into the old sod!
  3. If you do not want to look at the dead turf, cover it with mulch.

Resources

Rugged Country Plants

Natural Resources Conservation Service

University of California

 


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