April 28, 2005
9 ways landscaping can look AND be green
By MARK SINDELL
Population growth and development are changing the face of the planet. Habitat loss, climate change and shrinking resources are immediate problems impacting our daily lives. The choices we make for how we develop will affect quality of life for generations to come.
Site planning and landscape design can have a significant effect on resource use and natural systems. According to the Environmental Protection Agency, outdoor water use averages almost 40 percent of our total home water use. In Seattle, lawn and garden watering make up more than 40 percent of our summer water use, when resources are most scarce.
Landscape architecture traditionally held beauty, function and maintenance as fundamentals. Now an important fourth element is in play sustainability.
A sustainable approach strives to reduce demand on natural resources while enriching habitat. By taking some simple steps, we can realize the potential for lower utility bills, infrastructure savings, reduced maintenance, an enhanced idea of stewardship and an improved community environment.
1. Minimize disturbance
Carefully consider and evaluate existing topography and vegetation as part of the initial design process. Disturbing native vegetation displaces wildlife, causes erosion and directs sedimentation into waterways.
The long-term benefits of preserving existing vegetation can far outweigh the cost, materials and resources needed to establish new planting.
2. Invest in quality soil
Healthy soils recycle organic waste, reduce irrigation and fertilizer requirements and have a positive effect on stormwater quality and quantity. Topsoil, typically disturbed or removed entirely during construction, can be stockpiled and reused. Have soil samples tested by a certified soils laboratory.
Tilling imported composts and decomposed organics into disturbed soil will restore the soil's key natural functions.
3. Develop a design that contributes
Planting to mitigate climate conditions can reduce energy consumption and aid in passive solar design. Carefully placed groves of trees can serve as windbreaks or mitigate noise. Consider the long-term maintenance program for the site.
Publicly funded projects and parks are often restricted by limited maintenance budgets. A low-maintenance design that is harmonious with site conditions saves resources and eases demands.
4. Select appropriate plants
Planting design is no longer just about size, shape and color. A system-wide approach that takes advantage of site characteristics will save energy, cost less and simplify maintenance requirements over time. Consider the sun, soil, water and drainage characteristics during the seasons our Northwest weather often causes saturated soils in winter and dry soils in summer. Group plants with similar climactic requirements together.
5. Minimize lawn
Limit traditional lawn to active use areas. On large-scale housing and commercial projects, simply changing the lawn type and maintenance approach can save thousands of gallons of water and thousands of dollars.
There are many lawn mixes specifically developed for the Northwest that require less water and fewer fertilizers. Often referred to as Ecoturf, these mixes consist of lower growing drought- and shade-tolerant turf-type grasses like perennial rye grass, and waterwise broadleaf perennials such as English daisy, yarrow and strawberry clover. Give them appropriate care to get them established and have realistic expectations these lawns are more similar to meadows than golf courses.
6. Go native
Many of the invasive plants now choking our parks, streams and valleys were planted unnecessarily as garden exotics. Native and drought tolerant does not mean rough and ragged. Native plants can provide breathtaking fall color, fragrant flowers and quality form. There are ample garden-worthy cultivars to choose from. Our resilient Northwest natives are inexpensive, tolerant of acidic soils, establish quickly, provide habitat and require minimal watering and fertilization.
7. Use organic fertilizers, eliminate pesticides
Rainwater carries pesticides and fertilizers off our lawns and into our salmon streams through storm drains. Organic fertilizers, when carefully chosen and applied, remove the health and environmental impacts from quick-release chemical fertilizers.
Pesticides should only be used as a last resort. They are unnecessary with proper planning and are a health threat to children and pets. Beneficial insects and compost teas are safer alternatives.
8. Consider a green roof
Vegetation, habitat and green space aren't always on the ground. Consider a green roof where feasible. Vegetated roofs can protect roofing membranes from UV exposure and increase insulation. Simple roofing systems planted with drought-tolerant sedums require minimal soil depth, and if installed in the fall, no water for establishment.
Beyond adding aesthetic value, green roofs restore basic natural processes (such as evapotranspiration), easing demands on municipal systems.
9. Conserve water
New planting, regardless of how native or drought tolerant, requires water for up to two to three years for establishment. This can be achieved by a hand watering schedule or with a temporary irrigation system, decommissioned after establishment. If a permanent irrigation system is necessary, use high-efficiency systems (such as drip irrigation) and limit use of potable water.
Captured rainwater from roof runoff or gray water from building sinks and showers should be considered given requirements for the rate of rainfall, filtration, treatment and permitting.
There are a wealth of growing incentives and resources for sustainable design. Policies, rating systems including LEED and BuiltGreen, checklists and information for sustainable development are available on the Web and through public agencies such as Seattle Public Utilities.
The future holds great opportunity for developers, designers and homeowners to make a difference. Washington's population is projected to grow by 30 percent, reaching 8.3 million by 2030. We can choose to protect our shrinking resources. We can redevelop, reclaim habitat and reduce water use at the same time. A thoughtful approach to planting design will go beyond making beautiful places for work, play and respite yielding intrinsic value to a sustainable future.
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