Near the end of America's Gilded Age, the estate named Planting Fields was the home of William Robertson Coe, an insurance and railroad executive, and his wife Mary "Mai" Huttleston (née Rogers) Coe, the youngest daughter of millionaire industrialist Henry H. Rogers, who had been a principal of Standard Oil. It includes the sixty-five-room Coe Hall, greenhouses, gardens, woodland paths, and outstanding plant collections. Its grounds were designed by Guy Lowell, A. R. Sargent, the Olmsted Brothers, and others. Planting Fields also features an herbarium of over 10,000 pressed specimens.
In 1913, William Robertson Coe purchased the house and 353 acre (c. 1.4 square kilometres) estate, and began today's plantings and landscaping under the guidance of the Boston landscaping firm of Guy Lowell and A. R. Sargent. In 1915, Lowell and Sargent oversaw transport of the Fairhaven beech from Fairhaven, Massachusetts, the childhood home of Mary "Mai" Huttleston (née Rogers) Coe (who was the daughter of Henry H. Rogers of Standard Oil). Two gigantic beeches, with root balls thirty feet (nine metres) in diameter, were ferried across Long Island sound in mid-winter. Roads were widened and utility wires temporarily removed to make way. Only one of the two trees survived the journey. Unfortunately, the second beech tree has died, and was taken down in February 2006. However, the “Fairhaven Beech” will live on. Seedlings were collected from the tree from 2000-2005.
The property's first mansion burned to the ground on March 19 1918; its replacement, the present Coe Hall, was constructed between 1918 and 1921 in the Tudor Revival style and faced in Indiana limestone. It was designed by the firm of Walker & Gillette and was completed in 1921. Images from a book of English country houses and inspired its architecture, especially those of Moyns Park, Athelhampton, and St. Catherine's Court.
William and Mai Coe's interest in rare species of trees and plant collections made the estate a botanical marvel. Mai, who was chronically ill for the last decade of her life, died on December 28, 1924 at the age of forty-nine and is buried nearby. The 353 acre (1.4 km²) estate was deeded to the State of New York in 1949 (during Mr. Coe's lifetime) to become a state park.
A.R. Sargent created The Italian Blue Pool Garden between 1914 and 1918, with the Tea House built in 1915 to designs by Guy Lowell. Historically this garden was planted with spring-blooming perennials such as delphiniums, irises, peonies, and poppies. It is currently being restored to this original form.
After the death of A.R. Sargent in 1918, the Coes appointed the Olmsted Brothers of Brookline, Massachusetts, with James Frederick Dawson as chief landscape architect, who brought their signature "naturalistic" look to the north side of the property. They completed additions to the Main Greenhouse and Camellia Greenhouse, as well as the Beech Copse, Main Lawn, West Lawn and Heather Garden.
The Green Garden features a circular pool. Nearby Azalea Walks and Vista Path show hundreds of varieties of Azalea and Rhododendron. The Rose Arbor and Rose Garden contain over 680 Tea, shrub, and miniature roses.
The Synoptic Garden displays over 500 types of tree and shrub, arranged in alphabetical order by botanical name.
The Magnolia Collection contains over 80 types of deciduous and evergreen Magnolia.
The Camellia Greenhouse (Lowell & Sargent/Olmsted Brothers, 1917–1922) was built specifically to house the Camellia collection, which currently consists of over 300 plants. Some come from the Coes' original collection from the island of Guernsey.
The Main Greenhouse (Lowell & Sargent/Olmsted Brothers) was constructed between 1914 and 1929, with a Hibiscus House added in 1929 for the Coes' Hibiscus collection. Today, the Main Greenhouse offers large collections of orchids, cacti and succulents, houseplants, ferns and Begonias, as well as seasonal displays of Chrysanthemum, Poinsettia, Hydrangea, Coleus, etc.
The North Border features the Holly collection, Dwarf Conifer Garden, Conifer Trail, Heather Garden, and Species Rhododendron. The Holly collection includes over 100 different types of evergreen hollies such as English, American, Asian and hybrid forms. The Dwarf Conifer Garden features dozens of varieties of spruce, fir, Chamaecyparis, Juniper, Pine, etc. The nearby full-scale conifers can reach over sixty feet (eighteen metres) tall, and include Sequoia, Dawn Redwood, Larch, Fir, Spruce and Pine, with a large assortment of Rhododendron species under the canopy. The Heather Garden features low growing heaths and heathers, as well as Rhododendron, Azalea, and other flowering plants.
The Dahlia Garden offers several hundred varieties of show-quality Dahlias.
Finally, there are over 200 acres (c. 0.8 square kilometres) of woodland at Planting Fields, with miles of walking trails through the woods.
Planting Fields Arboretum was listed on the National Register of Historic Places in 1979.