Great Grounds Advice
By Dawn Klingensmith
At its best, landscaping isn't just pretty. It's purposeful, and sometimes political. Sustainable landscaping in public spaces demonstrates concern for, and commitment to, the local community.
With green maintenance strategies in place, including hand-pruning and eschewing pesticides, the Santa Barbara County parks department in California understands and exemplifies landscaping best practices. The Chicago Park District, which launched a PR campaign in defense of dandelions, also gets it.
But though it's true that modern landscaping best practices often emphasize sustainability, they also must take into consideration environmental psychology (the interplay between humans and their environment) and aesthetics.
Here, we show by example some basic, overarching principles and strategies of responsible landscape design and maintenance. We also spotlight three showcase parks that incorporate touchable clouds, a highway overpass, and a floating igloo, respectively. Finally, we present some nontraditional ideas to consider, such as urban agriculture and cement-crack gardens.
While landscaping, by definition, is part of the natural environment, it also can be a drain on natural resources. The best landscaping designs and programs seek to minimize the toll it takes on the environment.
"The primary concerns are water and power consumption," said Mark Robertson, principal, Mesa Landscape Architects, Little Rock, Ark.
As such, native and drought-tolerant plant species and turf grasses should be specified as a matter of course, but oftentimes they are not. "When it comes to plant material, people are still trying to use the old favorites. They're not trying to adapt to climate- or region-specific species," Robertson said.
Rainwater, soil moisture and air temperature sensors should be used to conserve water; however, "I can't tell you how many times I've seen irrigation systems going during a rainstorm" because the systems operate on set cycles, Robertson added.
"The old rule was a regular watering cycle that was not controlled or coordinated with actual conditions," he explained.
Of course, sports fields must be maintained so as to provide a safe playable surface, and failing to do so can be costly. That there were problems with the playing surface is a complaint lodged in many lawsuits after injuries occur. But though it is necessary to water and mow turf fields, "There are new ways of irrigating them, using sub-surface drip systems, to where you're only watering the root zone and not just dumping water on top," allowing much of it to evaporate, Robertson said.
Drip irrigation as opposed to spray heads saves water and is better for plant health, he added.
Storm water can be captured and retained onsite and infiltration used instead of piping and draining.
Where there are large areas of turf that require irrigation and where conservation is a concern, site managers can undergo a landscape audit, including an irrigation evaluation. Evaluations typically include measuring the sprinklers' distribution uniformity, a soil survey and recommendations for controller settings, and projections for potential savings.
Robertson likes to see landscaping projects get off the ground—literally. Installing green, or vegetated, roofs benefits an entire site by managing storm water runoff, mitigating the heat island effect and encouraging biodiversity. "A well-designed living roof can capture up to an inch of water so it never even touches the ground," he said.
More and more municipalities are recognizing the importance of green roofs in the urban landscape, and studies have shown that in addition to the environmental benefits, they have longer lifespans than traditional roofs. Yet other countries are light years ahead in their design and use.
Chicago leads U.S. cities in the building of green roofs, with more than 500 projects either finished or under way. However, that number represents less than one-tenth of 1 percent of Chicago's more than half a million buildings. By contrast, 15 to 20 percent of the flat roofs in Germany are green, because local governments there have implemented regulatory incentives for building green roofs including a "rain tax" that charges property owners for impervious surfaces that allow for rainwater runoff into sewers. Toronto last year passed a law requiring all new buildings with at least 2,000 meters of floor area to cover part of their roofs with vegetation.
Besides its green roof initiatives, Chicago for more than six years has avoided the use of chemicals in its parks. "Following natural lawn care basics, the park district keeps the grass 3 inches high, which allows the roots to grow strong and access water deep in the ground," said Zvezdana Kubat, assistant press secretary, Chicago Park District. "As a result, the taller grass naturally shades out some weeds. With the reduction in use of chemical weed killers, dandelion flowers grow back quickly, oftentimes overnight; therefore, we're spreading the word that the sight of dandelions indicates grass that is healthy and safe for patrons to play on."
The park district uses propane-powered, low-polluting lawnmowers and practices "grass-cycling," or leaving the clippings on the grass. "There's a significant amount of nitrogen in the grass clippings that acts like a natural fertilizer, helping provide nutrients to our turf grass in an environmentally friendly way," Kubat said.
Most turf grasses throughout the Chicago Park District are aerated rather than irrigated in order to help fight soil compaction, which is a common occurrence on lawns that are used as recreational surfaces. This helps water and nutrients reach the roots of the grass.
Santa Barbara County in California maintains 8,000 acres of parks and open spaces, and though different sites require different maintenance strategies, in all areas the county practices integrated pest management.
As a pilot effort for the past several years, Santa Barbara County has all but eliminated the use of herbicides and pesticides in one 680-acre region. This near-comprehensive proscription is occasionally reviewed on a case-by-case basis when a particular project requires very limited use of an herbicide—for example, to prevent reemergence of a non-native invasive plant in a native plant restoration project.
In this region, called South County, the ban has only been lifted once since 1997, to remove an invasive species that out-competes native plants for water.
A controlled flame with a burn bottle is used to kill weeds in parking lots, sidewalk cracks and decomposed granite areas, and black plastic covering is used to kill weeds in limited problem areas. The use of mulch in planter beds inhibits weed growth, while also discouraging snails and retaining moisture for plants.
Compost tea, made by steeping compost in water, is used throughout the county for fertilizing and soil enrichment. Eliminating regular use of broad spectrum herbicides does increase the amount of time and cost of weed abatement. In fact, the cost of mechanical weeding, including labor and equipment, costs the county up to 10 times more per square foot than for previous controlled use of herbicide.
"Sustainable landscaping on the whole can save money. North Lake College in Irving, Texas, in 2003 initiated a program to introduce native plants to the campus, with cost reduction as a primary objective (along with environmental stewardship, education and awareness, and aesthetic considerations). Since implementing the program, irrigation volumes have been reduced by 50 percent or more in converted gardens and landscapes. North Lake irrigates most of the campus with recycled storm water, and native gardens reduce usage in areas served by city metered water," said Grounds Supervisor Chris Marrs. Labor has been reduced by 70 percent, and seasonal plant material costs have been eliminated or reallocated.
Seattle University's grounds department maintains all outdoor areas on campus without the use of chemical pesticides, and has done so going all the way back to 1986. All landscapes are completely organic except for the athletic fields. The university does not see pesticide application as viable, even as a last resort. The grounds crew aims for weed suppression, not eradication, and also uses wood chip mulch, compost top-dressing, compost tea and beneficial insect release to achieve this objective.
After seven years of planning and building at a cost of $19.5 million, Chicago's new Mary Bartelme Park opened in August to considerable fanfare, including praise for its marriage of sustainable and imaginative design elements. The Chicago Tribune calls the park "geometrically complex, engagingly interactive and highly stylized." Its angular layout features a raised lawn in the center for lounging and picnicking. Diagonal paths cut across the park, and there's a series of large stainless steel structures that people can pass through like doorways and that release a cooling mist that forms clouds.
The steel structures form a path to the playground. Instead of trucking dirt from the excavation off-site, the dirt was formed into mounds on the playground. The Tribune reports: "Approaching, you see the mounds first. They endow the park with that rare thing in pancake-flat Chicago: topography." The tallest is about 7 feet high and provides a view of Willis Tower (formerly called the Sears Tower).
The park incorporates native plants and an abundance of reused materials, such as playground surfacing made from recycled tires and seating made with terra cotta lintels salvaged from the demolished university infirmary that occupied the site. The park also features some cutting-edge sustainable technologies, including "smog-eating" permeable pavers that absorb rainwater runoff and pollutants from the air using special cement that oxidizes the pollutants. The pavers reportedly stay cleaner than other products, thus reducing maintenance costs.
A degraded area beneath a highway overpass in Toronto will be transformed into a park. The park's design is influenced by the massive overpass columns and structures and will feature athletic courts, recreation areas for seniors, playgrounds and dining options, as well as community gardens. The existing site's eccentricities and built-in weather protection are integral to the design.
To park is lit by a combination of LED spotlights on the 50-plus overpass columns, shielded in-ground and in-wall lights and illuminated concrete ribbons at the seating areas. Sustainable features include granite cobblestones reclaimed from an avenue and landscaping designed for minimal irrigation.
The Indianapolis Museum of Art's new outdoor art park, 100 Acres, is a place where an ongoing commission of site-specific art appears out of the landscape and, in some cases, merges with and becomes part of it. The "site-responsive" art installations are set in woodlands, wetlands, meadows and even in the lake. Previously a gravel pit, the site has evolved through natural reclamation into its current state of untamed woodlands and wetlands.
One installation is a 50-foot-long boat that cuts across the museum's 35-acre lake. From a nearby guard tower, visitors can hear the voices of imaginary refugees fleeing an environmental disaster, as well as the sound of gunfire and other voices fretting about illegal immigrants trying to come ashore. Also in the lake is a floating fiberglass igloo that bobs around untethered and is accessible via rowboat.
Surrounding the lake is a continuous thread of yellow benches that have hills and dips, rather than platforms, for seating. One has been dubbed the kissing bench because when two people sit in it, they can't help but slide into each other.
Since a vegetable garden sprang up on the White House lawn, and as a consequence to the recession, the concept of urban agriculture is gaining traction and could positively address issues of food security, economic development, urban blight, waste recycling, environmental preservation, and land use planning and policy. Urban food plots would create educational opportunities addressing biodiversity, weather, lifecycles of organisms and nutrition. School districts could develop hands-on curriculums and field projects.
Perhaps incentives could be created for cleaning up and using empty lots for community gardens, though in some cities polluted soil could be a serious impediment. In addition, growing food in cities imposes new demands for water.
Rain gardens are planted for the purpose of reducing the amount of storm water entering streams, rivers and lakes. They are bowl- or saucer-shaped instead of mounded or flat like other perennial gardens, and make use of deep, loose soil to collect and absorb rain that would otherwise run off a site. Rain gardens are nothing new but warrant attention because they can be implemented on existing properties, providing educational opportunities and a gentle push toward larger initiatives and more holistic planning.
"Rain gardens are easy to do on an existing site, especially if you have a good team of people who are able to make sure the garden becomes well-established and is maintained properly," said Rachel Hood, executive director, West Michigan Environmental Council, Grand Rapids. "You have to think about maintenance. Make sure you have a maintenance plan and long-term support, and communicate with your maintenance staff."
With the help of area schoolchildren, "We have built some wonderful rain gardens on certain sites, only to have contractors mow over them entirely," she added.
"Industrial-strength" rain gardens are possible where there are large-scale storm water management requirements. An environmental engineer may need to weigh in on the design to ensure proper drainage.
The American Society of Landscape Artists offers awards for careful stewardship, wise planning and artful design, and recently conferred an award for sustainable landscaping on a residential project is San Francisco. The idea could be replicated by municipalities where expanses of concrete pose environmental threats and aesthetic challenges.
Designed and installed by the homeowners for just $500, the "crack garden" was originally an area of poured concrete that retained excess heat in the summer and increased water runoff to the surrounding area. The homeowners took jackhammers to the concrete, creating cracks for plantings. The cracks extended down to the soil, turning the impermeable slab into a permeable and attractive garden space with retained hard surfacing for furniture and such. And many of the plants were chosen for their ability to tolerate foot traffic, so use of the space isn't
necessarily limited on account of the interruptions in concrete.
The garden consists of flowers, herbs, vegetables and "even aesthetically pleasing rogue weeds," according to the ASLA Web site.
While imagination and innovation certainly exist in parks and recreation landscape design and practices, and while low-cost solutions like the San Francisco crack garden annually receive attention, Robertson of Mesa Landscape Architects worries that short-sightedness and bottom-line concerns affect landscaping decisions for the worse. "There's a lot of room for improvement in selection of landscape lighting choices, for example," he said. "As a whole, we've got to do a better job of assessing life cycle cost vs. front-end or initial cost."
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