From Erica Maust, of the Woodlands Historic Mansion, Cemetery, and Landscape:
“In 1784, William Hamilton introduced the Lombardy poplar to North America on his Philadelphia estate, The Woodlands. In 1788, a visitor to The Woodlands wrote that Hamilton’s walks were “planted on each side with the most beautiful & curious flowers & shrubs. They are in some parts enclosed with the Lombardy poplar except here & there openings are left to give you a view of some fine trees or beautiful prospect beyond…”
Grove Street Cemetery in New Haven, Connecticut was the first private, non-profit cemetery in the world. Organized in 1796 as “the New Burying Ground in New Haven,” it was one of the earliest cemeteries to have a planned layout with privately owned family lots, named streets and avenues, and arrangements of ornamental plantings. The original 1796 planting scheme of the cemetery featured regular rows of–you guessed it!–Lombardy poplars (the very same tree Hamilton introduced to North America 12 years earlier), along with a poplar grove and meadow at the rear of the cemetery.
44 years later, in 1840, Hamilton’s very own landscaped Woodlands became a planned, rural cemetery, preserving his landscape and horticultural pursuits.”
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And for more about William Hamilton and the Lombardy poplar:
Growing History 