Helen Byrne employed James Leal Greenleaf between 1904 and 1910 to create a spatial plan for the Byrnes' new estate at Planting Fields. Greenleaf is responsible for the Green Garden Court and Circular Pool in the Cloister area, and the Rose Arbor. On other estates on Long Island, Greenleaf did more extensive work, mostly formal gardens and estate layouts. Some other residential work on the Island that Greenleaf designed gardens for are: Mortimer Schiff estate "Northwood: in Oyster Bay (1905) Herbert L. Pratt estate "The Braes" in Glen Cove (c. 1912) George D. Pratt estate "Killenworth" in Glen Cove (c. 1912) Harold I. Pratt estate "Welwyn" in Glen Cove (c. 1913) In 1921, the Architectural League of New York awarded the Medal of Honor to Greenleaf for Landscape Architecture for his work on the Pratt estates. He is still considered a pioneer of spatial planning in landscape architecture.