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Archaeologists find hidden African side to noted 1780s Enlightenment building in Maryland, U.S.

February 14, 2011
University of Maryland
A famous US Revolutionary-era building -- lone-surviving testament to an Enlightenment ideal -- has a hidden West African face, archaeologists have discovered. Their excavation at Maryland's 1785 "Orangery" -- the only 18th century greenhouse left in North America -- reveals African American slaves played a sophisticated, technical role in its operation. They left behind tangible evidence of their involvement. Frederick Douglass, who made it famous in his autobiography, failed to appreciate the slaves' full contribution, new research suggests.

One of North America's most famous Revolutionary-era buildings -- a lone-surviving testament to an Enlightenment ideal -- has a hidden West African face, University of Maryland archaeologists have discovered.

Their excavation at the 1785 Wye "Orangery" on Maryland's Eastern Shore -- the only 18th century greenhouse left in North America -- reveals that African American slaves played a sophisticated, technical role in its construction and operation. They left behind tangible cultural evidence of their involvement and spiritual traditions.

Frederick Douglass, who lived there as a young man, made it famous through his autobiography. But the team concludes that he failed to appreciate the slaves' full contribution.

"For years, this famous Enlightenment structure has been recognized for its European qualities, but it has a hidden African face that we've unearthed," says University of Maryland archaeologist Mark Leone, who led the excavation. "Concealed among the bricks of the furnace that controlled the greenhouse temperature, we found embedded a symbol used in West African spirit practice. An African American slave built the furnace, and left an historic signature."

His team also found African charms buried at the entrance to a part of the Wye greenhouse that once served as living quarters for the slaves who maintained the building.

"Ironically, these African symbols distinguish this building from its more elaborate European counterparts, and give it a unique American character," Leone adds, who has uncovered other evidence of African spirit practice through his Archaeology in Annapolis project.

African American Contributions

The slaves were pioneers in early U.S. agricultural experimentation, the new research concludes. They did far more than manual labor, performing work that today might be conducted by skilled lab technicians, though under far different conditions.

"These greenhouses were for agricultural and horticultural experimentation in 18th century America, and African American slaves played a far more significant and technical role in their operation than they've been given credit for," Leone says. "This work required sophistication and skill, and the slaves provided it." For example, slaves began experimenting there with wild broccoli and other greens, Seneca snakeroot as a cure-all, ginger root for tea, buckbean as an analgesic and antiemetic, and hardy bananas.

European Contributions

Leone says that Enlightenment ideals of beauty, natural order and scientific understanding made greenhouses important to colonial-era estates in America and across Europe. His excavation at the Wye greenhouse revealed the European tastes of its owners.

Rare Pollen Analysis

Based on an analysis of centuries-old pollen recovered from the site -- a rarely used procedure in historical archaeology -- plus written historical records, Leone says the greenhouse started with a range of flowering plants, shrubs, and medicinal herbs. By the 1820s, more exotic plants were cultivated, including lemon and orange trees, and possibly tubs of pond lilies. This corresponds to Frederick Douglass' descriptions in his autobiography.

The Wye "Orangery" stood on the thriving Lloyd Plantation, a large operation with several hundred slaves. The property, first settled by Edward Lloyd I in the 1650s, is still owned by his descendants. The family has encouraged the excavation for the historical and scientific knowledge it can provide.

Frederick Douglass

The building's fame stems, in large part, from the garden's description by Frederick Douglass. In his "Narrative of the Life of Frederick Douglass, An American Slave" (1845), Douglass wrote: "Colonel Lloyd kept a large and finely cultivated garden, which afforded almost constant employment for four men, besides the chief gardener," he recalled two decades after leaving the plantation. "This garden was probably the greatest attraction of the place. During the summer months, people came from far and near -- from Baltimore, Easton, and Annapolis -- to see it. It abounded in fruits of almost every description, from the hardy apple of the north to the delicate orange of the south."

Writing in 1855 ("My Bondage and My Freedom"), Douglass identified the greenhouse chief as Mr. McDermott, the "scientific gardener imported from Scotland," and again, noting his team.

Pollen analysis confirms the broad sweep of plant life grown in the greenhouse, as Douglass describes it. In turn, his writings provide historical markers in the evolution of the greenhouse. But the total archaeological record suggests Douglass did not recognize the skilled work the greenhouse slaves performed, Leone concludes.


  • Slaves constructed the brick and mortar furnace that regulated temperature in the greenhouse. Evidence for this comes from the excavation's discovery of a concealed West African-style charm cemented among the bricks at the rear of the furnace where it connects to ductwork -- a spot where no one would see it, since spirit practice was conducted in secret. The African America builder of the furnace had placed a stone pestle there to control spirits. This corresponds to the Yoruba practice of placing an old, sharp object from the ground there, Leone says. The pestle was discovered by Drake Witte, who rebuilt the furnace and repaired the heating conduits.
  • Slaves lived in the greenhouse, where they could operate the heating system -- the "hypocaust" -- and maintain the heat, light and water required by the plants. The team recovered evidence of domestic life in one of the greenhouse's three rooms. Most recently the area has been used as a potting shed. But, buried underground were fragments of earthenware and other domestic objects. Leone says the loft in the room was likely used for sleeping. By the door, the team also unearthed another set of West African charms -- a coin and arrowheads -- placed there to manage spirits.

Systematic experiments were conducted in the 18th and 19th centuries to determine optimum light, temperature and water requirements of exotic plants, and slaves took an active role in this work. "These buildings were not only for beauty or display," Leone says, drawing on historic records and modern scholarship. "Plantation owners like the Lloyds also were conducting agricultural experiments out of economic necessity and by the temperament of the times. They wanted to have access to exotic plants, and they wanted to learn how to make them thrive. They approached this in a systematic way, and it's no stretch to consider this scientific experimentation."

Furnace operators -- the slaves -- would have had to monitor conditions and maintain temperatures within the recommended range of 42 to 54 degrees F, Leone adds. Working under a Scots gardener, they would have to read the thermometer, understand each plant's requirements, control the windows and monitor the furnace. The knowledge and skill acquired from these experiments became one of the slaves' possessions, and helped createan African American tradition of gardening.

Harrison Roberts, born a slave at Wye House, continued the gardening tradition there and died in the 20th century. He mastered the skills while a slave and continued to use them after freedom. "The knowledge didn't just go away -- it endured longer than the plantation system," Leone concludes, based on an oral history from the 1960s.

  • Evolution from greenhouse to orangery -- pollen analysis and Frederick Douglass tell the story. In the late 18th century, the greenhouse had a range of flowering plants, shrubs, and medicinal herbs. Over time, the plant arrays expanded, and by the 1820s citrus and more exotic species were cultivated. Lemons and oranges grew there, as did members of the rose family, lily, saxifrage, phlox, iris and members of the nightshade family. Evidence for this comes from pollen excavated from the greenhouse by the team and analyzed by specialists. Historic records and descriptions also supplement the picture, especially the autobiographical writings of Frederick Douglass, who spent his early years as a slave on the Lloyd Plantation.
  • Look of the greenhouse: Anything in the greenhouse would have been potted or in a trough of some sort, and these would have been in tiers or placed on risers, Leone explains. The plants would probably have been kept in groups, which was the preferred technique shown in gardening manuals at the time.
  • The 1785 greenhouse was built on top of an earlier one. Around 1770, Edward Lloyd IV built his first greenhouse. In 1784 or 1785 he started again -- the building that stands today, equipped with a hypocaust. At Leone's request, Bryan Haley, of the Center for Archaeological Research at the University of Mississippi (now of the Tulane Department of Anthropology), used extensive soundings from a magnetometer and ground penetrating radar to discover evidence of the larger, earlier structure. Haley's analysis showed what may be the underground remains of structures attached to the original greenhouse, which did not have a heating system within it. This would have been a garden pavilion that used either the heat of the sun or the heat from piles of dung kept inside.

Pollen Analysis

To analyze the traces of old pollen found buried in the greenhouse soil, Leone consulted with a palynologist. It's the first time the technique has been used on an historic U.S. greenhouse, Leone says. Research scientist Heather Trigg at the University of Massachusetts, Boston's Fiske Center for Archaeological Research was able to identify families of plants grown in the greenhouse. "The technique often does not permit the identification of specific species," Trigg explains. "Pollen from the rose family was identified in the soil of the greenhouse, for example, meaning that rose, strawberries, or some wild plants, such as cinquefoil, were grown there."

Lloyd Descendants

The Orangery remains active today, maintained by descendants of Edward Lloyd IV, who first started construction on it even before the Revolutionary War. The excavation was launched at the request of the family, and preceded structural work to maintain the building.

"I'm committed to preserving the history of this building and the entire estate," says Mrs. R.C. Tilghman, an 11th generation descendant of Lloyd. "This land has always been a part of my life, and its preservation comes as a duty."

The Tilghmans permitted Leone to conduct an earlier series of excavations on the property, which uncovered slave quarters and other buildings.

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University of Maryland. "Archaeologists find hidden African side to noted 1780s Enlightenment building in Maryland, U.S.." ScienceDaily. ScienceDaily, 14 February 2011. <>.
University of Maryland. (2011, February 14). Archaeologists find hidden African side to noted 1780s Enlightenment building in Maryland, U.S.. ScienceDaily. Retrieved July 15, 2024 from
University of Maryland. "Archaeologists find hidden African side to noted 1780s Enlightenment building in Maryland, U.S.." ScienceDaily. (accessed July 15, 2024).

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