Climate-Conscious Gardening
Join Master Gardeners in the Arlington/Alexandria unit of Virginia Cooperative Extension in a series of monthly articles in 2021 as we explore the topic of climate change and practical actions individuals can take in their home landscapes in response.
By Elaine Mills, Extension Master Gardener
A blog post from November 2020 by Extension Master Gardener Wendy Mills clearly outlined the environmental issues posed by our love affair with lawns in the United States: heavy use of limited water resources, pollution of waterways through the overuse of fertilizers, negative impacts to wildlife from herbicide and pesticide applications.
In addition, the care of our lawns takes a heavy toll on our time and money as homeowners try to meet the unattainable goal of the perfect, unblemished expanse of green. The average household spends $1,200 and 70 hours annually on lawn care, although many individuals consider mowing to be an onerous chore.
There are quite a few challenges to growing lawns. For starters, despite names such as “Kentucky bluegrass” and “Bermuda grass,” turf grasses are non-native species from Eurasia and Africa. They have shallow root systems that don’t absorb rainwater well. Because some grasses are warm-season plants and others are cool-season plants, no single species looks good all year round, and most don’t grow well in the shade. Grasses are also generally incompatible with trees, which prefer more acidic soil and can be damaged by mowing and string trimming of the surrounding lawn.
There are a number of actions that climate-conscious gardeners can take to make their lawns more environmentally friendly. One consideration is to reduce areas of the yard devoted to turf grass. Rather than being used as the landscape default, grass can be one design element in an overall garden plan. Lawn can be retained in play areas for children or dogs; it can serve as footpaths in heavily traveled areas; and it can be used as edging in limited areas to define planted flower beds. The remaining landscape can feature an expanded plant palette of small trees and shrubs, perennials, summer annuals, vegetables, and herbs. (See recorded public education classes under Sustainable Landscaping in our Master Gardener Virtual Classroom for information and inspiration.)
Next, homeowners can take steps to maintain any existing turf grass more sustainably. Mowing lawns less often will reduce the use of fossil fuels in gasoline-powered mowers and switching to push mowers will eliminate toxic gas emissions and the chance of fuel spills. Setting the mower height to 3 ½ or 4 inches promotes root growth of grass, increasing its drought tolerance, shading the soil, and discouraging weeds.
Other helpful practices include retaining grass clippings as a natural mulch, and aerating to provide oxygen to the root zone. From 1/4/ to ½ inch of aged compost can be added to the top of an existing lawn to restore soil structure, nutrients, and soil microbes, either before or after aeration. Another possibility is allowing the lawn to go dormant as seasonally appropriate. That means that cool-season grasses will naturally be less green in the summer and warm-season grasses will turn tan in the winter.
David W. Wolfe of Cornell University has a number of additional suggestions which can improve nitrogen use efficiency for lawns. Homeowners can select grasses such as fine fescues which have relatively low nitrogen requirements and could consider introducing clover, which, as a legume, fixes nitrogen in its roots. He also recommends using organic sources of nitrogen, such as manure and compost. If synthetic fertilizer is used, urea is preferable to either ammonium sulfate or ammonium nitrate as its production results in fewer greenhouse gas emissions.
Another possibility is the use of low-maintenance lawn alternatives. No-mow fescue blends can be used in sun to part shade, are drought-tolerant, and tolerate moderate foot traffic. Buffalo grass (Buchloe dactyloides), native to the Midwest, spreads quickly from plugs, can handle arid summer conditions, and requires little to no mowing. Locally native Pennsylvania sedge (Carex pensylvanica) has a grass-like appearance and is a good choice to cover areas of dry shade, especially when stepping stones or other pathways are provided for foot traffic.
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Poverty oat grass (Danthonia spicata), a native cool-season species utilized in the native lawn demonstration area at Cornell Botanic Gardens, does best when combined with some low-growing woodland or meadow plants such as spring beauty (Claytonia virginica), moss phlox (Phlox subulata), bluets (Houstonia sp.), and plantain-leaved pussytoes (Antennaria plantaginifolia) to fill in between patches and add color. Using herbaceous plants as ground covers in lieu of grasses in another solution. See the recorded public education class “Native Ground Covers for Sun and Shade” for recommended species for a variety of landscape situations.
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The July article in this series will provide more details on making wise choices of plants for residential landscapes. In June, we will be exploring adaptive climate-conscious techniques as they apply to home vegetable gardening.
Resources
- Native Lawn Demonstration Area. Cornell Botanic Gardens.
- Simmons, Rod. 2019. “Lawn Alternatives.” Maryland Department of Natural Resources.
- Wolfe, David W. 2011. “Gardening Sustainably in an Uncertain Climate.” The New American Landscape, Ch. 6. Timber Press.