by Sanne Kure-Jensen Low maintenance and the benefits of native plants were recurring themes in the presentations at the 17th annual Ecological Landscape Association Conference held March 7 at the Mass Mutual Center in Springfield, MA. Seeing Green: Design Strategies for Urban Landscapes “Landscape designers can help prevent sprawl by creating livable cities, encouraging people into cities to live, work and play by giving them opportunities to enjoy green space in their neighborhoods,” said Tobias Wolf of Wolf Landscape Architects. People want to get away from gray [spaces] and into the green.” Where sites and budgets allow, he recommended designing with closely planted material; be sure to establish a strong maintenance plan so the garden will stay lush and healthy. Ideal conditions, like those at the Mandarin Oriental project in Boston, allowed a “terrarium” plan, where the planting can be dense and enveloping. Wolf described another projects in Illinois which called for the “pavement crack” approach where site conditions are left as is and plants are selected for their ability to survive and improve those conditions. Any project lies somewhere on that continuum; the important thing is to know where and select plants accordingly. When designing for city gardens, courtyards and parks, mimic early successional ecosystems. These plant communities will have the greatest chances of success in urban conditions. These plants are the most adaptable, and most are readily available in regional nurseries. Wolf urges work to reduce the ecosystem fragmentation in urban areas, one park at a time. He urges planting lush spaces with high biodiversity by making sure there are a wide variety of trees, shrubs and perennials, not just an isolated row of uniform trees planted 20 feet apart. To entice visitors into public garden spaces, include a variety of flow-
ers. Don’t feel compelled to limit your palette to long-blooming flowers; be open to briefly blooming flowers, spring ephemerals and natives which can give the landscape a fresh look with each visit. Low mow grasses and native plants should reduce future maintenance costs and fuel use. When planting over parking garages or on roof tops, Wolf described a project where he installed at least 1 foot of soil for turf, 2 feet or soil for shrubs and 3 feet of soil for trees. The growing media blend will need to vary based on the load capacity of the structures. As with land-based parks, designing with rolling ‘hills’ helps create mystery in a design and helps draws people in. To help build height when there isn’t weight capacity, use layers of solid foam building insulation. Be sure to leave space between the panels to drain excess moisture. Plants should be selected to thrive with available soil, light, moisture and wind conditions. Red Maple, Sassafras, Bald Cypress, Winterberry Holly and Mountain Laurel are among Wolf’s favorite woody plants. Lawns are a luxury. Wolf minimizes lawns because of their high input needs and maintenance costs. Turf or lawns are often requirements of public spaces; Wolf makes them as small as possible and frames them with sharp lines to show how special they are. In non-turf areas, he recommends blending plantings gently by feathering transitions between masses of various plants. He also recommends including stone walls for added seating; be sure think beyond standard park benches. Wolf shared tips he has learned and design successes. • Paths in urban gardens should have long sight lines for increased safety, but that doesn’t mean that they need to be boring or uneventful. • Moveable chairs should be heavy enough that they don’t blow over but light enough that people can move them
Kevin Staso of North Creek Nurseries describing native plants from various ecosystems, each suited to specific site conditions.
Tobias Wolf, of Wolf Landscape Architects, recommended designing with closely planted materials. Photos by Sanne Kure-Jensen to be comfortable. • When planning to use large diverse plantings or ornamental grasses, frame them with curbs or paved paths and viewer are less likely to complain about the “weedy” mess. • When working with clients describe the environmental benefits of rain gardens and bio-swales before showing photos with native or traditional wetland plants and be sure to use images that can give clients a clear understanding of the potential appearance of their landscape. Some customers may be turned off by the ‘weedy’ or ‘messy’ look of native wetlands. Consider signage to educate future visitors. Native Plant Communities Suited to Urban Sites Many city dwellers escape cities on weekends because they grew up with woods and in suburban and rural settings and they miss that connection with nature. Kevin Staso of North Creek Nurseries described harsh city environments offering blinding sun, sharp reflections, wind tunnels, drought, extreme temperature fluctuations, air pollution and contaminated soils. Given these site conditions, it is no wonder that most city landscapes struggle to find an appropriate balance. Communities with vegetated bus stop shelters, lush parks and rain gardens can improve the quality of city life and encourage people to stay and enjoy their neighborhood parks. Plants and the color green, by nature calms people, helps reduce tension and lowers blood pressure. Staso described a variety of wonderful urban parks including The Hudson River Park in Manhattan, the High Line and the many efforts of the City of Portland, OR, which has substantially invested in its 10,000 rain garden initiative for decentralizing storm water miti-
gation. In St. Louis, the Laumeier Sculpture Park successfully encouraged people to stay and enjoy their city park for lunch breaks, an afternoon stroll or a weekend family picnic. The success of the park has transformed the downtown area for St Louis. “Amended soils are overrated,” said Staso. His take on the “Right Plant, Right Place” motto is “Identify the plants that will thrive in the existing conditions for the most successful projects.” Parks work when designers pay attention to plant needs, site conditions and match plant communities to site conditions. Issues can include soils compaction, heavy metal contamination, trash, pet waste and even threats from nature herself: rabbits, turtles, geese and deer browsing. Be sure to note stormwater inundation cycles, drought or watering opportunities and schedules and road salt risks. Prairie grasses, warm season grasses and short grass meadows can be planted in the poorest compacted soils or brown fields and thrive with minimal maintenance after establishment. Native plants offer minimal maintenance after establishment. Staso recommended establishing a new urban garden using a layered approach of plants rather than isolated specimens or stands. Denser plantings create stronger and more beneficial relationships among plantings, reduce fragmentation and often allow animals and insects a corridor within the park or garden. Another benefit to native plants is the diversity of colorful native pollinators that will visit the garden or park. For new urban plantings, start with full sun lovers. As the tree canopy matures, add more shade tolerant plants. Urban plantings like any other planting need to evolve.
Page 3 - Section A • COUNTRY FOLKS GROWER • April 2012
Designing with diverse, native ecosystems