The Hirshhorn Museum's sculpture garden and plaza is a landscaped open-air gallery- a contemplative haven in the heart of a major urban center. Despite its serene appearance, the garden had a tumultuous birth.
The original idea for a rectangular sunken garden on the National Mall was conceived in 1966 by Nathaniel Owings of the international architecture and engineering firm, Skidmore, Owings and Merrill of New York City. Gordon Bunshaft, another partner with the firm, carried out Owings' idea. Bunshaft's original plan in 1967 called for a two-acre sunken garden that would bisect the Mall and be oriented perpendicular to the future Hirshhorn Museum which would be located just across the street. The garden would be 7 feet below ground level with 3 foot high walls creating an enclave that was 10 ft. deep. A 506 x 60 foot rectangular reflecting pool would dominate the space while the surrounding walkway would be covered with pebbles. It was an austere Minimalist design with few trees, bushes, or flowers.

The original Bunshaft plan created much controversy and work on the project was halted by Congress in January 1971. The following month, Benjamin Forgey, then art critic for the Washington Star newspaper, wrote an article that proposed some solutions. He suggested making the reflecting pool smaller, turning the garden parallel to the Mall and moving it closer to the museum. He also suggested adding terraces and plants to soften the space. New plans incorporating these ideas were approved in July 1971.

When the redesigned 1.3 acre sunken garden finally opened in 1974, it was a neutral setting where the sculptures commanded much of the attention. It featured a center court 14 feet below ground level with a rectangular reflecting pool and two flanking terraces. Enclosed within high walls, the garden floor was covered with pebbles, had no grass, and only a few plants. The garden's shortcomings soon became evident, however. The pebbles were difficult to walk on. There was no access for strollers or wheelchairs. There was not enough shade. It was truly a hot, stark, and bleak space.

In 1977, architect Lester Collins of the Innisfree Foundation redesigned the sunken garden to make it more user friendly. His goal was to provide ramps for easier access and to soften the area with extensive plantings. Construction began in 1979 and the garden reopened in 1981. Today the sculpture garden features verdant, manicured lawns. The pebbles are gone and the large, harsh open area has been divided into more intimate spaces. Because the sculptures are exhibited on a rotating basis, the landscaping is not designed around individual pieces. It is a calming green space with weeping beeches, pines, and crepe myrtles. Clematis and ivy climb the enclosure's walls.

The Hirshhorn museum and plaza garden area also opened in 1974. Seventeen years later, because of the plaza's deteriorating concrete surfaces, it was necessary to renovate the outdoor space. In 1991, landscape architect, James Urban of Annapolis, Maryland, in collaboration with the museum staff, redesigned and renovated the 2.7 acre area that surrounds the circular building. A wheelchair entrance to the Mary Livingston Ripley Garden next door was added. It linked to a newly installed pathway inside the plaza that runs parallel to the wall around the entire site thereby encouraging visitors to see the sculpture from the outer reaches of the plaza. Today, grassy areas for sculpture resembling "rooms" and divided by rows of flowering trees are situated in the plaza's four corners. Slightly smaller spaces for sculpture amid small groves of honey locust trees are situated along the plaza's east and west sides. The Hirshhorn's immense circular fountain remains the focal point of the plaza area.

The sculptures that adorn the garden and the plaza were originally owned and displayed on the 22 acre Connecticut estate of Joseph H. Hirshhorn. Although the Hirshhorn Museum's plaza and sunken garden cover approximately 4 ½ acres, more than 60 works of art are displayed in these outdoor areas year round. The museum and the garden are located at Independence Avenue and 7th Street, SW.