An integral component of the renovation and restoration of Hillwood Museum and Gardens was the extensive work done on the designed gardens that surround the mansion. In planning the gardens in the 1950s, Marjorie Merriweather Post consulted with well-known landscape architects Umberto Innocenti and Richard Webel of Long Island, NY and local landscape architect Perry Wheeler, who assisted with the establishment of the Rose Garden at the White House. The original plan combines twelve acres of formal gardens with thirteen acres of native woodland beyond.

Hillwood’s gardens include a circular rose garden, where Floribunda roses bloom around a granite monument holding Mrs. Post’s ashes; a "Friendship Walk," dedicated to Mrs. Post for her philanthropic generosity by a group of friends; a formal French parterre just outside the drawing room of the mansion; a large crescent-shaped lunar lawn; a Japanese-style garden and waterfalls representing a mountain landscape in miniature; a greenhouse for orchids; a large cutting garden; and a pet cemetery with small inscribed tombstones and statues of dogs. The garden walkways are accessible to visitors with disabilities.

As Mrs. Post intended, the gardens served as outdoor extensions of the mansion’s interiors and functioned as essential areas for entertaining and fundraising events. In particular, the elegant French parterre complements the adjacent French Drawing Room. "Mrs. Post designed each of the garden rooms to flow logically from one to the next," said Gwen Stauffer, Director of Horticulture at Hillwood. "The design of the garden is influenced by European styles that directly coincides with the collection."

French Parterre
The French parterre, one of Mrs. Post’s favorite gardens, was extensively restored. Designed by Innocenti and Webel more than forty years ago, the garden showed severe signs of age and degradation.  The limestone rills and curbstones for the beds were cracking, the drainage system under the garden had collapsed and failed, and some of the sculpture had weathered harshly.  Also, numerous features altered in attempts to make repairs or to prevent further damage had to be returned to their original design intent.

"Part of my job was to look at the garden through Mrs. Post’s eyes so we could recreate the original design intent and repair years of alterations," said John Sonnier, staff project manager of the renovation of the French parterre. Sonnier, who worked with local architect Richard Williams, did countless hours of detective work, extensively researching in the Hillwood museum archives; interviewing Alfred Manfree, the original parterre designer from Innocenti and Webel; visiting several of Mrs. Post’s former estates to study the gardens; and conducting an archeological-like excavation of the existing garden.

A new drainage system, waterworks, and limestone features were installed in the garden, and the appropriate glass tile was located in Mexico and relaid in the pools at each end. In addition, restoration treatment was applied to the sculptures in the French parterre, including two 18^th-century white marble sphinxes, six 19^th-century French limestone urns from Paris and a terracotta replica of a marble Diana sculpture at the Louvre. Also, the severely weathered swan fountain was painstakingly removed and replicated in a more durable Tennessee pink marble to capture the former glory of its design and detailing.

Father and son team, Constantine and Andy Seferlis, two well-known Washington stone carvers and sculptors, worked together to replicate the swan fountain. Constantine Seferlis is best known as one of the principal sculptors of the Washington National Cathedral’s many gargoyles and embellishments.

Another component of the restoration of Innocenti and Webel's design for the French parterre was the reintroduction of a decorative ivy back plate surrounding the swan fountain, and a trellis system comprised of aluminum panels was custom designed to protect the structural integrity of the building. All plants were removed from the French parterre during the rebuilding of the garden infrastructure, and afterward the four parterres were replanted with the original hedging boxwood, and the same variety of azaleas, arbor vitae, juniper, and yew were planted in terrace beds and along the balustrade.

Additional Sculpture and Furniture
The many works of sculpture and pieces of furniture throughout the gardens also were restored or recreated.  Intricately carved limestone fruit baskets in the front circle were treated and re-carved at the base and 19th-century Parisian urns at the entrance to Hillwood were completely recreated by Constantine Seferlis. In addition, the majority of metal garden furnishings were refurbished, while most of the wooden furniture had to be replicated.  All of the mahogany pieces, which were custom made for Mrs. Post, were carefully replicated in the same graceful lines of the originals and replaced were originally used, with the help of archival images.

Plantings
Because Mrs. Post planted Hillwood's landscape with mature specimens more than four decades ago, the horticulture staff implemented a preservation plan to rejuvenate old plant specimens and restore the botanical collections. In fact, the entire azalea collection has been undergoing a rejuvenation program since 1994. In some cases mature plants were replaced with new ones of the same species and variety. However, some are no longer available, leading the staff to propagate existing plants to ensure accurate replication.

Precautions also were taken to preserve the existing plant collections, in particular the American elms on the south side of the house. The horticulture staff worked with professional arborists to protect the trunks of these trees during restoration with a protective "armor" of wooden planks wired together. In addition, to protect the root zone and prevent soil compaction by heavy equipment, a conveyor belt moved soil between work areas.

In other sections of the gardens, entire portions of the plant collections were removed or transplanted into storage during the construction process. Along with the plants from the French parterre, the large southern magnolia on the side of the Porte Cochère and the adjacent trees and shrubs were removed to accommodate the large-scale restoration projects around the mansion. Additional improvements are planned for the future, when the Japanese-style garden designed by Shogo J. Myaida, will be extensively restored.