Across the country, visitors to arboreta are coming face-to-face with the exciting fruits of the Green Revolution.
By W. Barksdale Maynard
In Seattle, plant ecologist Kern Ewing leads a group of volunteers through a wetland on the windy shores of Union Bay. They’re here to help restore the landscape by planting native trees, because this apparently natural environment is actually a former city dump where tons of garbage lie hidden beneath reeds and cattails.
The 76-acre wetland forms part of the University of Washington Botanic Gardens, created in 2005 alongside (and incorporating) historic Washington Park Arboretum. “Restoration strikes a chord with the public,” says Ewing, and arboreta everywhere desperately need to lure the public in these times of economic distress and dwindling endowments. Americans are enthusiastic about ecology right now, he says, and volunteers love getting their hands dirty in restoration work. More and more arboreta are undertaking creative projects of this kind, Ewing adds — making valuable “friends for life” in the process.
Arboreta really need such friends. Nationwide, public gardens of all kinds receive 70 million visits a year, but those numbers are slipping at many places, several worried directors told American Forests. “Young families are not interested in being outside,” laments Rick Colbert, director of venerable Tyler Arboretum in Pennsylvania, which was founded by two tree-loving Quaker brothers in 1825. “Kids today are much more comfortable behind a computer screen.”
How to reach this fickle new generation? One solution is to tap into the themes of sustainability and “going green,” subjects of tremendous enthusiasm right now. Arboreta everywhere are trying this new approach — and none too soon, says Colbert: “There’s lots of competition out there, and arboreta must become relevant. We cannot be in our ivory towers anymore. We either change and grow, or slip back and die.”
Sustainability is far more than a marketing ploy. It goes to the heart of what the modern arboretum wants to be. “Arboreta are perfect places for people to understand sustainability,” argues Mary Meyer, interim director of the Minnesota Landscape Arboretum, which increasingly models the green approach, from irrigating plants only at appropriate times of day, to banning the sale of bottled water for drinking. “People look to arboreta to be leaders,” she explains.
Daniel J. Stark, executive director of the American Public Gardens Association, agrees: “Of all cultural organizations, public gardens and arboreta should be playing a leadership role in demonstrating sustainable practices.”
Across the country, visitors to arboreta are coming face-to-face with the exciting fruits of the Green Revolution. High in the Appalachians near Asheville, the North Carolina Arboretum is showing off three new buildings that use of cutting-edge technologies: green roofs, geothermal wells, and rainwater catchment systems. Not only has the arboretum’s approach taken a dramatic turn toward sustainability, but the visitors themselves have also become more demanding. “It’s not like it was 25 years ago,” says Clara Curtis, director for design. “Back then, educational programming consisted of slide lectures. Today, people want hands-on workshops and demonstrations. They want the real thing.”
These newly engaged guests come seeking lessons applicable to their own lives. How can they make their lawn and garden back home more sustainable? One answer lies in composting, as arboreta are increasingly demonstrating. At Scott Arboretum, which embraces the entire campus of Swarthmore College in Pennsylvania, every stick and leaf that falls is composted offsite for a year, then hauled back to the grounds as mulch.
At Bartram’s Garden, America’s oldest arboretum (founded by colonial plantsman John Bartram in 1728), composting has begun in earnest. Interns mix grass clippings, leaves, and horse manure into an odiferous, fertile blend. For director Louise Turan, it’s all part of a larger effort to make every visit “more relevant to one’s individual life. Gardens that do this will have more success than those you just come to look at.”
As part of the sustainability push, many arboreta are promoting recycling. At Morton Arboretum outside Chicago, visitors stroll along a new path made of crushed beer bottles mixed in a chemical polymer. In addition to using repurposed materials, the walkway’s porous surface allows rainwater to percolate gently through, reducing dirty runoff that contributes to groundwater pollution.
In the past, dead trees arboreta were trucked away to rot. But increasingly, downed wood is now being ingeniously recycled as a positive example to the public. Last year, Bartram’s Garden suffered a devastating storm that damaged 36 trees and flattened five, including a historic cucumber magnolia that was 190 years old. All the wood was recycled as logs for use as furniture, boards, or decorative bowls, or as chips to be strewn as mulch.
At Morton Arboretum, recycling street trees has become an urgent priority. Such trees are almost never commercially harvested, and as a result, the equivalent of 3.8 billion board-feet of lumber is dumped into American landfills every year. With millions more ash trees on Midwestern streets expected to die from the emerald ash borer (see sidebar), Morton recently exhibited attractive furniture made from diseased ash wood, to encourage sensible use of this vast, untapped resource.
Many Americans are concerned about spiraling energy costs and needless waste of resources. Arboreta are specifically addressing these concerns. The United States National Arboretum in Washington, D.C., recently exhibited crops suitable for biofuel production, and installed six solar panels to run a drip irrigation system in its nursery. Next year, the North Carolina Arboretum will undertake a campus-wide survey of energy and resource use, taking the form of a detailed report card.
And in a much-publicized initiative, the United States Botanical Garden and Lady Bird Johnson Wildflower Center have partnered with the American Society of Landscape Architects to create the Sustainable Sites Initiative (SITES), a national rating system promoting “greener” landscapes. This new outreach complements the popular Leadership in Energy and Environmental Design (LEED) program of the U.S. Green Building Council, which focuses on building systems and materials. Trees are central to a number of the SITES guidelines, including planting shade trees on the south side of buildings to
reduce the need for air conditioning. Arboretum directors are paying close attention to SITES, and frequently mention it as a bellwether for future developments in eco-friendly landscaping.
Suburban homeowners looking to reduce water consumption can learn much from arboreta. The U.S. National Arboretum has plans to install a rain garden in its parking lot, and the high-maintenance lawn on the arboretum’s famous Ellipse (fronting the Capitol Columns) will no longer be mowed. Lately, the Morton Arboretum has been educating visitors about cisterns, including new types powered by the sun. A dozen years ago, Scott Arboretum installed a pioneering “bioswale” of river rocks to catch storm water; now its new Wister Education Center and Greenhouse has a cistern for irrigating a nearby garden, and two rain gardens catch water running off from the parking area. Five acres of lawn on campus may soon be treated organically, instead of being sprayed with pesticides.
Last year, the Minnesota Landscape Arboretum exhibited new types of grasses for suburban lawns, including two native species — June grass and tufted hair grass — that require less coddling than typical bluegrass or fescue. The public response was enthusiastic.
Among other ecological benefits, native plants often need much less water than exotic species. Through talks with garden clubs, Crosby Arboretum in coastal Mississippi advises against landscaping with exotics, which can run rampant in a semitropical climate. Still, locals are hesitant to give up their favorite non-natives. As Director Janine Conklin says: “They really love their hydrangeas!”
For over 50 years, the Minnesota Landscape Arboretum prided itself on developing cold-hardy trees and shrubs, including exotics. Today, these are falling out of favor. Students touring the facility recently commented that the breeding of rhododendrons and azaleas runs contrary to new sustainability ethos. Though pretty, such plants are unsuitable to the alkaline soils of the upper Midwest. Director Meyer thinks the arboretum will turn toward breeding more native plants instead.
Of course, the heart of any arboretum is its trees, and advertising their benefits has never been more important. “People don’t feel the connection to the trees that our forefathers did back when they didn’t have TV and air conditioning,” says Justin Evertson, green-infrastructure coordinator for the Nebraska Statewide Arboretum. His organization, a coalition of 90 arboreta, parks, and campuses across Nebraska, works to educate the public about trees, especially their benefits for water management in that drought-prone prairie region.
Environmental consciousness has grown slowly. “Tree planting has not kept up with tree removal,” Evertson complains, and replacement trees are often the wrong kind. After Dutch elm disease destroyed many street trees in Omaha, they were replaced with silver maples. “Boy, do they fall apart in our storms,” Evertson says.
Wild, tree-decimating weather seems to be the rule lately. The East Coast was buried under record snows last February, followed by the hottest July ever recorded. Climate change may be the culprit. Arboreta need to begin educating the public about this contentious issue, urged several speakers at the recent 4th Global Botanic Gardens Congress in Dublin, Ireland, which Kern Ewing and many other American arboretum experts attended.
“The new forefront is going to be climate change,” agrees the North Carolina Arboretum’s Clara Curtis. “We need to educate visitors on a nonpolitical basis about how climate affects growing and living.” As arboreta redefine their missions and refocus their priorities for the 21st century, the impact of climate on the growth of plants and trees — and on our lives generally — promises to be an important direction. Today’s emphasis on sustainability is extending deep roots, and coming years will likely see the full flowering of this dynamic new approach at arboreta everywhere.
—W. Barksdale Maynard has authored five books on American history and landscape. He has taught at Johns Hopkins and the Princeton Environmental Institute.
This article was published in the Autumn 2010 issue of American Forests magazine.