The Tregaron Estate is a national landmark, a remarkable aesthetic achievement and treasured part of Washington DC history. As owner and steward of its historic landscape, the Conservancy is dedicated to preserving this important part of our history, recapturing its beauty and continuing to share its story.
The Estate, built in 1912, was designed by renowned architect Charles Adams Platt and landscape architect Ellen Biddle Shipman, a pioneer in her field. Together, they transformed 20 forested, steeply-sloped acres into a magnificent estate featuring a naturalistic yet intensively designed landscape. This dramatic landscape was by far the largest woodland garden designed by Shipman, and is one of the very few remaining gardens of its type.
Learn more: read the full history here
First, there was the Twin Oaks Estate:
In the 1880s, around the time that President Grover Cleveland was seeking refuge from the city by buying a summer home in what is now known as Cleveland Park, other Washingtonians were doing the same. Gardiner Greene Hubbard, a wealthy lawyer and founder of the National Geographic Society, purchased a tract of land between today’s Woodley Road and Macomb Street on which, in 1888-89, he built a splendid early Georgian Revival-style summer house which he named Twin Oaks.
Modeled after the grand estates of Newport, Rhode Island and designed by the Boston architectural firm of Allen and Kenway, the 26-room estate commands its site high on a hill above the residential neighborhood. Set on a wooded knoll, dropping steeply to two branches of Rock Creek, Twin Oaks was named after a large twin-trunked oak tree on the property. (The Twin Oak eventually landed on the portion of the property now owned by the Tregaron Conservancy.)
Twin Oaks Estate served as a summer gathering place for the extended Hubbard family. One of Hubbard’s two daughters, Mabel, married Alexander Graham Bell, inventor of the telephone. Hubbard’s other daughter Roberta married Charles J. Bell, the banker and cousin of the inventor. Gardiner Greene Hubbard played a significant role in the invention and subsequent distribution of the telephone. Upon his death, Hubbard’s property was divided between Roberta and Mabel. Roberta kept the Twin Oaks Estate, while Mabel inherited the undeveloped 20 acres to the east of Twin Oaks.
Roberta Hubbard Bell kept the Twin Oaks estate in her family for quite some time. Finally, after renting the property for 10 years, the Government of the Republic of China purchased the Twin Oaks Estate from Grace Hubbard Fortescue in 1947 to make it the official residence of each successive ROC ambassador. Following the change in diplomatic relations between the ROC and the United States, Twin Oaks changed owners.
The house has been owned by the government of Taiwan since 1982. In 1986, Twin Oaks was placed on the National Register for Historic Sites. The Taipei Economic and Cultural Representative Office in the U.S. (TECRO) operates Twin Oaks as a center for diplomatic and social gatherings. Twin Oaks survives as the sole remaining example of late 19th-century summer house architecture in northwest Washington.
Next came the Causeway Estate, designed by architect Charles Adams Platt and landscape architect Ellen Biddle Shipman:
Meanwhile, in 1911, Mabel Hubbard Bell (Mrs. Alexander Graham Bell) sold her undeveloped share of the Twin Oaks property to James Parmelee, a financier from Cleveland, Ohio. Parmelee was looking to build a year-round country house with views of the then-new National Cathedral. (Parmelee and his wife Alice Maury were major benefactors of the Cathedral and are buried in its crypt.)
The Parmelees hired Charles Adams Platt, the premier architect of the American Country House Movement, to design their new home. In 1900, Platt’s office was one of the New York firms that dominated the general development of American architecture, and his country houses and Georgian-style mansions were regarded as the finest American examples of their genre.
The estate was originally named “The Causeway” by Parmelee, in reference to the handsome stone bridge and entry drive to the estate from Klingle Road. Platt designed the buildings and gardens to relate to each other as an integrated whole, carefully planning vistas from the buildings to specific landscape features, and vice versa. In so doing, Platt was inspired by Italian villa design, which promoted the concept of the house and environs as an integrated whole.
At the time the Parmelees purchased the property, the landscape was primarily woodland of varying topography, two streams and a cow pasture bordering Klingle Road. Platt drew on these features, taking full advantage of topography and vistas. He chose the summit of the hill for the new house, designing a brick Georgian Revival mansion to crown the hill, in keeping with many of the District’s larger homes. The mansion affords long vistas to the north and south. The northern view shed looks features an undulating meadow to a bridle path and stream surrounded by mature trees. Also visible from this vantage point are small stone bridges and retaining walls. The southern vista overlooks an open lawn bordered by trees and shrubs, the sweeping causeway and pond valley. Like the northern vista, stone hardscape features and the bridle path are visible.
In 1912, Charles Platt hired Ellen Biddle Shipman for landscape design work at the estate. Shipman is widely recognized for her contributions to the field of landscape architecture, particularly as a horticulturalist. Tregaron was the second collaboration between Shipman and Platt (and is the only surviving one). While Platt planned the circulation pattern for the site along with the formal gardens – it was Shipman who completed the plans in 1914. She provided planting plans for the gardens and 20-acre grounds. Tregaron is by far the largest woodland garden that Shipman designed in her long and illustrious career.
Platt and Shipman’s core design was based largely on Beaux Arts principles, aligning the buildings and formal garden in axial relationships to each other, relying on design principles to optimize views and vistas.
The 1915 book American Country Houses of To-Day by Samuel Howe includes a lengthy description of The Causeway as an example of a desirable lifestyle. The formal flower garden provided a place to walk and hold intimate conversations. The sweeping lawn, beyond the formal garden and embraced at its lower end by the woodland/pond garden, provided more dramatic views of the larger landscape and the distant city. Perhaps the landscape’s most intriguing feature was the bridle path, winding along the eastern edge of the property, crossing under the causeway and them meeting the drive at the property’s northern end. Experienced as a whole, the estate’s landscape was more like that of an isolated country manor than of a house at the edge of the nation’s capital.
Platt’s landscape centered on using the existing bridle path as a spine, bringing together the various parts of the landscape. The bridle path’s careful plantings marked it as a highly designed environment. The design invited the visitor to be actively engaged with the site: there was no single vantage point from which all views could be enjoyed. As professor and author Thaisa Way writes: “The Parmelees could ride horses or walk along the path, which began in the woodland garden following the edge of the hill to the opposite end of the estate. The path predated the Shipman/Platt design, having originally circumnavigated the entire hill. Shipman and Platt used the path to bring together the parts of this larger landscape, like gems on a necklace.”
The Causeway, with its beautiful landscape of diverse gardens, in many ways exemplifies the partnership between Platt and Shipman. For more information on Platt, see Keith N. Morgan’s Charles A. Platt: Artist as Architect (MIT Press, 1985) and Shaping an American Landscape: The Art and Architecture of Charles A. Platt (University Press of New England, 1995).
In 1915, Shipman designed plantings around the pond, causeway, bridle path and brook. Her December 1915 plan, presented to the Parmelees as a Christmas gift, incorporated the cow pasture, existing canopy trees, the stream, and the bridle path, the design carefully woven into the landscape. Looking at the 1915 plan (which the Tregaron Conservancy follows closely for its restoration work), it is noteworthy how the existing topography and waterway are used to create a naturalistic woodland of native and naturalized plants. The path follows the course of the stream, with pockets of sun and water offering variety and interest. This woodland garden was unlike Shipman’s other know garden designs, relying on an informal composition of naturalized plants around a pond. Masses of color and texture were blended to form irregular beds enhancing the undulating topography, the site’s hydrology, and the existing trees.
By 1920, Shipman maintained an independent landscape practice, though she continued to collaborate with Platt on residential projects. In 1927, the Parmelees hired Shipman again to design a wild garden for The Causeway. Photographs of the woodland design show a complex scheme incorporating mixed drifts of ornamental exotics with indigenous plants. Period images show a woodland canopy shadowing large stands of rhododendron and lush ground-level plantings, opening to sun-drenched clearings. A rare sense of ease emanates from these garden pictures. Shipman had a continuing relationship with the landscape, designing different, detailed sections of the property over many years. For a complete list of plants that Shipman designed and incorporated into The Causeway (now Tregaron) landscape, see Ellen Biddle Shipman Plant List from 1919.
In 1933, House & Garden named Shipman the “Dean of Women Landscape Architects.” Her gardens often appeared in magazines, including House Beautiful. She lectured widely and completed over 600 projects. Shipman died in 1950 at the age of eighty.
According to independent landscape historian Judith Tankard, “by 1950, most of the 600 gardens that Shipman had designed during her lifetime had changed beyond recognition. Many were simply gone, and her work was quickly forgotten. Ellen Shipman’s talent — an extraordinary talent — had escaped documentation in the annal of American landscape history.” However, Shipman’s archives are maintained at Cornell University.
For more information about Shipman, see The Gardens of Ellen Biddle Shipman by Judith B. Tankard (Sagapress, Inc., 1996) and Unbounded Practice: Women and Landscape Architecture in the Early Twentieth Century, by Thaisa Way (University of Virginia Press, 2009).
The Causeway is purchased by Marjorie Merriweather Post and Ambassador Joseph Davies and renamed Tregaron Estate:
In 1940, after the death of the Parmelees, Ambassador Joseph Davies and Marjorie Merriweather Post purchased the Causeway Estate. Davies had served as U.S. Ambassador to the Soviet Union and Post was a leading socialite and the owner of General Foods, Inc. They renamed the estate “Tregaron” after Davies’ mother’s ancestral home in Wales. “Tregaron” means “Caron’s Town” after an early Welsh saint who founded the church in a small village in Wales.
The Davieses made a number of changes to the estate: They hired a local architect to design a Russian dacha or folk house (reminiscent of their time in the U.S.S.R.); once built, the Davieses set the dacha in a quadrant of the Shipman formal gardens to take advantage of the Cathedral views. They also altered the landscape by slightly regrading it for installation of a golf course, added fountains and painted the bottom of the lily pond turquoise.
The estate was the site of many prominent social gatherings, during both the Parmelee and Post/Davies eras. Newspaper accounts describe many society gatherings, including teas, balls, and parties. Notable visitors included three U.S. Presidents (Roosevelt, Truman and Eisenhower). Ambassador and Mrs. Davies also opened their home to benefit various charitable causes ranging from National Symphony performances to the American Merchant Marine Library. A May 1944 article in Life magazine features Tregaron’s elegant mansion and gardens.
The Davies-Post residence period at Tregaron spans from circa 1941 to 1958, when Davies died. He and Post divorced in 1955 at which time Post moved to the Hillwood Estate, a short distance from Tregaron. Davies stayed on at Tregaron following the end of their marriage. After 1958, Tregaron continued with limited use and very little upkeep for approximately 20 years as the disputes among the Davies heirs were settled. From 1959 to 1979, the landscape evolved without significant staffing and management. The land was open but was unoccupied and neglected.
In January 1979, Tregaron was designated a Historic Landmark of the District of Columbia.
Post-Davies’ Era: Tregaron is divided and threatened by housing development plans
In 1980, Tregaron was split into two lots and sold. The Washington International School (WIS) — which had been renting the buildings — purchased six acres encompassing the historic buildings at the estate’s hilltop — the mansion, the greenhouse, the gardener’s cottage, the carriage house and the farmhouse.
The remaining 14-acre, undeveloped portion of the estate — including many notable landscape features –was purchased by a Tregaron Limited Partnership (TLP), a real estate investment partnership, which then made a series of attempts to gain approval for housing developments. The TLP land extended downslope to the property boundaries to the north, east and south.
In the many years that followed, the Friends of Tregaron (the community organization that preceded the nonprofit Tregaron Conservancy) and other stakeholders fought to preserve the land from development. As mentioned, the estate became a DC Historic Landmark in 1979, and in June 1990. In June 1990, the entire estate, including the landscape, was listed on the National Register of Historic Places. Although the Tregaron Estate had significant historic and legal restrictions, TLP continued its efforts to turn the estate’s woodlands into a housing subdivision ranging from 9 to 200 houses. The Friends of Tregaron and community successfully resisted these efforts, appearing at many hearings before the DC Historic Preservation Review Board (HPRB). The HPRB has 19 Tregaron case files regarding development proposals. Here are a few:
These housing development proposals failed due to significant historic and legal protections. Ultimately, after years of negotiations, TLP agreed to donate 13 of its 14 acres to a newly-formed land conservancy. (The remaining acre was sold for residential development as part of the agreement.) The agreement, signed on January 24, 2006 by TLP, WIS and the Friends of Tregaron Foundation, set forth the timing and details of the contribution of real property to the Tregaron Conservancy. In addition, there are deed restrictions on the very limited development that was allowed, as well as conservation easements granted to the Tregaron Conservancy. The Conservancy holds the deed to the property and is restoring, maintaining and operating the land. The Tregaron Conservancy has chosen to open the privately-held property to the public for its enjoyment.
As steward of one of the very few preserved Shipman designs, the Conservancy is fortunate to have — at last — the larger picture of her work and design philosophy to guide us as we continue our exciting and challenging landscape restoration work at Tregaron.
Learn more about the Conservancy’s first decade of work transforming Tregaron from a severely degraded, environmentally damaged landholding to a treasured woodland gem.
The Conservancy’s current projects mark the start of an exciting second decade of work to advance our mission. We hope you will be inspired to join us in restoring and stewarding this beautifully serene, historic landscape for all to enjoy.