Green Museums (Part III): Pittsburgh Botanic Garden

Dogwood blooms and birdboxes in the 8-acre meadow

Dogwood blooms and birdboxes in the eight-acre meadow

Imagine a 460-acre parcel that has been deep mined, surface mined, farmed by several generations,  and abandoned. Now, after more than a decade of brownfields reclamation and remediation, the place is bursting with pride as the Pittsburgh Botanic Garden. Read the story: how it was done, what’s coming this spring and summer, and plenty of photos and videos. This article is Part III of the Green Museums series Parts I-III exclusively in Green News Update.

“This is a story of regeneration and resourcefulness,” says PBG President Greg Nace. “We are healing the land from decades of abuse.”

Coal extraction is part of the reclamation process

Coal extraction is part of the reclamation process

It has been no cakewalk. PBG has spent more than a decade on reclamation and remediation: collapsing abandoned mine tunnels that date back to the 1920’s, removing coal from the site’s ridgetops,  cleaning up flowing streams, and creating an intelligent rainwater system to help irrigate the 460-acre property. Its recent and planned projects – made possible because of the successful reclamation –include a native tree arboretum, heritage orchard, woodland garden, and Mr. Rogers’ Garden of Make Believe, among others.

This is much more than a “green museum” story: PBG may be the world’s only large botanic garden that has been created from brownfields.

Check out spring/summer events in 2014.

Read the full story below and access videos and other links

The early years

In July 1988, a half-dozen horticulturists and landscape architects convened over beer and bratwurst at Max’s Allegheny Tavern on Pittsburgh’s North Side. Their idea?  Create lasting horticultural improvements in the Pittsburgh region, with legions of local gardeners and other community enthusiasts.  A month later they formed the Horticultural Society of Western Pennsylvania.

They couldn’t have imagined the many roads they and countless volunteers would travel in more than a quarter century– and the complex projects needed – to transform the region’s sixth largest brownfields site into the Pittsburgh Botanic Garden (PBG), a model of reclamation and the planned home of  native and display gardens, walking trails, native tree arboretum and public education facilities.

PBG’s early years involved local, small-scale plant and garden projects that gave way in 1993 to a professional site selection process for creating a botanical garden, with criteria for a buildable site with good topography, and close to Pittsburgh.

Old Pittsburgh courtesy of city

Old Pittsburgh courtesy of city

Pittsburgh itself in the 1990’s was ramping up with a Downtown Partnership, and then a Pittsburgh Downtown Plan in 1998, with lots of foundation support that would steamroll the city’s amazing transformation after a century of steel production and  heavy manufacturing.

McGill Farm early 1940's is now part of the Pittsburgh Botanic Garden. After the mining started, the water on the farm was no longer potable, accird to a McGill descendant.

McGill Farm early 1940’s is now part of the Pittsburgh Botanic Garden. After the mining started, the water on the farm was no longer potable, according to a McGill descendant.

That same year, Allegheny County stepped up to offer a site that looked like a dream deal for the proposed botanic garden:  432 acres in the southwestern corner of Settler’s Cabin Park, about 25 miles from center city Pittsburgh. The County Commissioners loved the idea of having a new attraction in their area. They offered the nonprofit botanical group a renewable, 99-year lease.

Former mines and fouled waters

Everyone knew that the center of the property had been deep mined and also surface mined for the coal that once helped Pittsburgh thrive as an industrial center. What the garden founders did not know was that three of the property’s four streams – a natural source of irrigation for landscape and garden operations – were fouled with acid mine discharge. Iron pyrite in the abandoned mine shafts combined with oxygen and water to produce acid mine runoff, made up of salts and heavy metals, including iron, manganese, nickel and cobalt. Moreover, the ridges above the abandoned mines still held coal.

This created “dead” streams that could not sustain plant or animal life, and were unusable for irrigation. (In 2004, six inches of rain from Hurricane Ivan caused the mines to overflow; flooding and landslides resulted, with acidified water and sediment.) As tributaries of the Ohio River, they presented a larger danger of polluting a major source of drinking water.

Reclamation comes first, but not quickly

It’s a testimonial to the Pittsburgh Botanic Garden board and many partners that, rather than walking away from a really challenging and costly situation, they committed to more than a decade of careful reclamation, remediation and innovative water management in several phases.

Aerial picture of reclamation site

Aerial view of reclamation underway on the middle top ridge at the Pittsburgh Botanic Garden. Due to the large amount of acid mine drainage the Garden is in the midst of a complete reclamation project.

First there was the issue of the abandoned mines and subsurface coal on three ridges.   As they discovered, the Pittsburgh Coal Seam (its official name!) still held 26% coal. The ridges were first deep mined (1920’s); later, the two southern ridges were surface-mined (1940’s). That left a lot of unwelcome problems: high walls, mine subsidence and acid mine drainage.

With the approval of Pennsylvania’s Department of Environmental Protection (DEP) and federal agencies, PBG got the okay to extract the coal from 72 acres of abandoned mines, a process known as “day-lighting”—an effort that began in 2010 and continues today. After the residual coal is extracted, the mines are collapsed, filled in and contoured with soil to begin rebuilding the health of the land.

Reclamation work underway onReclamation work underway on the 72 acre mining parcel the 72 acre mining parcel

Reclamation work underway on the 72 acre mining parcel

The Garden gained approval to clear ridgetops of “overburden” left from mining –removing rocks and coal to a depth of 16-20 feet. This has been essential for future Garden uses: it stabilizes the land for landscapes, trees and buildings, cleans the water and reduces pollution entering the streams.

The solution is far from cheap, but PBG devised an innovative approach: Mineral rights for the site were donated to the Garden (2005-06) and the sale of the coal is funding site reclamation. Details on the reclamation process. 

Innovations in water management and irrigation

The “daylighting” of the abandoned mines was a critical step in addressing conditions that created an unstable environment and acid mine runoff. However, the reclamation was not complete:  a permanent system was needed for clean water – natural irrigation –to avoid costly municipal water bills in the future.

Reclamation in progress and one of the permanent irrigation ponds

Reclamation in progress and one of the permanent irrigation ponds

The solution? Three permanent irrigation ponds were created and supplemented with a 400,000-gallon underground cistern. That’s enough storage – some 2 million gallons of rainwater a year– to get the gardens through a droughty season. “Even with a dry summer, says PBG President Greg Nace, “our water system will ensure the Garden is properly irrigated without the significant expense of bringing in municipal water.”

Early funding came from Pennsylvania’s Department of Environmental Protection Growing Greener II Grant to expand erosion and sedimentation ponds into irrigation pond (2009); then a $510,000- PENN VEST grant for the underground cistern.  And there were important in-kind contributions – such as several hundred tons of limestone used in the water system.

Woodland Gardens Pond

If you look at today’s Woodland Pond you’d never know it had been dead for years, polluted with acid mine runoff flowing 10 gallons a minute from a pipe extending out of an abandoned mineshaft.

Woodlands pond

Woodlands pond

“Today it’s got life for the first time in 80 years,” says PBG President Greg Nace. There are peepers, minnows and crappies. It attracts insects and birds. The restored pond will be encircled by a Japanese Garden (now being designed) at the foot of the Asian Woodlands. (details below)

The passive water treatment system is a drainable limestone bed, filled with 450 tons of

Pouring floor of the pond

Cistern floor being poured

crushed limestone. Water is filtered through the limestone to a drainable 24,000-gallon tank before it enters the pond to reduce the acidity. Once a week, the tank is flushed and the water diverted into a settling pond where salts and metals can be removed.   It’s a marvel: “In just two days, says Nace, “the 2.9 pH water improved to 7.1 pH.” Tadpoles have been spotted in the pond! Details on pond restoration

A second pond is being used to feed the Garden’s tree nursery using a solar-powered pump.

Storing water in a special cistern

PBG broke ground in November 2012 for the 400,000-gallon cistern, which was completed in April 2013. It was tested by emptying the pond just above it into the enormous cavity. It’s watertight, and a smart, natural solution for irrigation management –a hedge against drought and extended hot periods that would otherwise require buying municipal water. Altogether, the ponds and cistern will provide over 2 million gallons of rainwater a year. Cistern construction details   

An ambitious vision

PBG Master Plan 2012

PBG Master Plan 2012

Reclamation and remediation have opened the door to PBG’s future – and it’s an ambitious long-term plan:

  • Promote sustainable design and judicious use of natural resources.
  • Conduct research to solve horticultural and environmental problems.
  • Build a garden representative of the eco-region and promote preservation of its native plants; collaborate on protecting threatened plants of the region.
  • Provide educational/professional opportunities for children adults, gardening and environmental professionals.

Check out the plan

Garden projects underway: A sampler

Entrance Road Rendering by MTR

Entrance Road Rendering by MTR

The three ridges, lowered as a result of the coal extraction, radiate in three directions from the garden’s core visitor complex – each focused on a theme: education, display and conservation. Between them are deeply forested valleys. The master plan envisions 18 distinctive gardens, themed woodland areas with trails including an ADA compliant trail, an amphitheater, and places for kids.

Walking trail in the woodlands gardens

Walking trail in the woodlands gardens

Here’s a sampler of what is happening and ahead:

Arboretum phase: Woodlands of the World

PBG’s conservation gardens on the north side feature Woodlands of the World, a 60-acre expanse that will showcase five distinctive woodland areas: Asia, Eastern Europe, England, Appalachian Plateau and Cove Forest. Some 27 acres have been cleared of invasive plant species. This area will present temperate forest species, restore the native habitat and promote biodiversity.

The restored Woodland Pond, nestled in the Asian woodlands, will be encircled by a meditative Japanese Garden, designed by California landscape architect Keiji Uesugi who has created similar gardens with his father for California  cultural institutions.

Restored woodlands pond in December 2012. It will be encircled by a Japanese garden, now being designed.

Restored woodlands pond in December 2012. It will be encircled by a Japanese garden, now being designed.

A heavy dose of volunteer support from the Boy Scouts, area business volunteers and people in the community has advanced the woodlands project: for instance, acres have been cleared of invasive plant species and planted with over 2,000 native trees, herbaceous shrubs, perennials and bulbs. An ADA-accessible trail over a mile in length winds back from the 1870’s barn on the property (under renovation as the visitors’ center) to form a loop through the different woodland gardens. A solar-powered irrigation system waters the young trees.

The woodlands are planned to attract insects, birds and wildlife. Over the past three years, the bird count has climbed to over 89 species, and there’s evidence of deer, coyotes and foxes.  This area is already open for hour-long “peek and preview” walking tours guided by volunteers who also catalog the animal life they observe.

PBG volunteers are part of the planting crew

PBG volunteers are part of the planting crew

Sprout Tree Nursery

The Sprout Tree Nursery, built in 2011, includes a greenhouse, composter and solar-powered irrigation system. It is a strategic investment that allows PBG to purchase younger trees and grow them for the reforestation program.  The nursery stock includes black walnuts, American beech, tulip poplar and a variety of oaks, in addition to espaliered apple trees. Details on the nursery

Replanting the American Chestnut

Chestnut roof beams at the PBG barn from the 1880's

Chestnut roof beams at the PBG barn from the 1880’s

A handsome 19th-century barn built of American chestnut on PBG’s property is a powerful reminder of the majestic chestnut that once filled North America’s eastern forests. It’s said that one of every four forest trees was an American chestnut in the early 20th century. Chestnuts were a workhorse tree that served many purposes: an ample food supply for forest wildlife and source of wood to build furniture, houses, musical instruments, even telephone poles. Then, a pathogenic fungus Cryphonectria parasitica arrived with the import of Asian chestnuts (naturally resistant to it); over time the fungus girdled the tree at its base,  by obstructing the natural conduits (phloem and xylem) for water and nutrients. Billions of mature trees were lost.

Female flower of the American chestnut. Courtesy of TACF_femflower

Female flower of the American chestnut. Courtesy of TACF

At PBG, it’s a great conservation story that the garden has been selected as a site to plant and grow the new hybrid strain of the American chestnut tree. And the spacious, 1870’s chestnut barn—now called the Bayer Welcome Center — is being repurposed and renovated as the garden’s visitor center! Scientific American article on the new American Chestnut

Heritage Buildings and Heirloom Orchard

Log cabin from the 1700's with the recently planted heirloom apple orchard

Log cabin from the 1700’s with the recently planted heirloom apple orchard

At the front door of the Woodland Gardens are several heritage buildings that date from times when the property was owned by early settlers who farmed the land:  a 1784 log cabin once belonged to Isaac Walker (a Revolutionary War veteran) and a farmhouse built in 1855. The cabin is being repaired for use in programming. Work on the farmhouse for administrative offices began in January.

The remnants of the farm’s apple orchard in the 1880’s have been transformed as PBG’s two-acre Heirloom Apple Orchard, with five varieties of trees – one dating to the 16th century and another from New York State called the Spitzenberg, which was Thomas Jefferson’s favorite variety. Funding from the Laurel Foundation supported the orchard and cabin projects. Volunteers contributed to the project by building split rail fences around the orchard perimeter and around each tree. Details on the orchard  

Volunteers fencing each of the apple trees -- protection from critters and weather!

Volunteers fencing each of the apple trees — protection from critters and weather!

An opening date – coming up

An 8-acre meadow features over 550 native white-flowering dogwood trees, now a rare collection due to ravages of disease over the past 25 years.

An eight-acre meadow features over 550 native white-flowering dogwood trees, a rare collection due to ravages of disease over the past 25 years.

Peek and preview guided walking tours of the woodlands are already being conducted on a regular schedule. Scouts and volunteer groups are busy improving the property,  enhancing visitors’ understanding of the natural history of the reclaimed land.

This summer (2014), parts of the garden will be open to the public. “We haven’t set a definite date for opening, “says Greg Nace, “but we’re talking about the first week of August. The Garden Writers Association will be here the beginning of August and we hope to give them a tour just prior to the opening.”

Pittsburgh Botanic Garden is a complex work in progress, but the original mantra of its founders– “in our lifetime” – is going to be fulfilled,  with legions of volunteers, partners and community supporters.


Video links

The Garden’s Vision

Follow the progress