When Post cereal heiress, art collector, social figure, and philanthropist Marjorie Merriweather Post left to the public her northwest Washington, D.C. estate, Hillwood, 4155 Linnean Avenue NW, Washington, D.C., she endowed the country with the most comprehensive collection of Russian Imperial art outside of Russia, a notable 18th-century French decorative art collection, and — of most interest to Road Trips Gardeners — 25 acres of landscaped gardens and natural woodlands. Ms. Post, the only child of cereal magnate C. W. Post, bought Hillwood in 1955. It was opened as a public institution in 1977.

With terraces and porches on all sides, the mansion was designed to allow easy access to
the outside. Between 1955 and 1957, Ms. Post hired prominent landscape architects Umberto Innocenti and Richard Webel, to expand the existing gardens.

Thirteen acres of formal gardens flow from the house in a progression of “outdoor rooms.” Each of these rooms, meant to complement the mansion’s indoor spaces, is decidedly private yet connected to adjacent gardens through subtle transitional features. The Innocenti and Webel-designed French Parterre, featuring typical formal elements of an 18th-century French garden, serves as a complement to the 18th-century French art and furnishings, providing a glorious view from the decidedly French-feeling master bedroom. Just beyond, lies the Rose Garden, redesigned shortly after Ms. Post acquired Hillwood by landscape architect Perry Wheeler. Other highlights of the gardens include the Japanese-style Garden (pictured, right), a testament to the taste for oriental gardens influenced by the reintroduction of Japanese culture to America during the 1950s; the Friendship Walk, and the Lunar Lawn, a large, crescent-shaped lawn that provides a view of the Washington Monument.