Question: What is the name of the 4.2 acre public garden in the Smithsonian complex, adjacent to the Smithsonian Castle on the National Mall in Washington?

Context articles: Enid A. Haupt Garden
White House Astronomy Night
S. Dillon Ripley Center
Smithsonian station
Smithsonian Gardens
National Museum of Natural History
Public Garden (Boston)
National Mall
Boston Common and Public Garden
Friends of the Public Garden

The Enid A. Haupt Garden is a 4.2 acre public garden in the Smithsonian complex, adjacent to the Smithsonian Castle on the National Mall in Washington, D.C. It was designed to be a modern representation of American Victorian gardens as they appeared in the mid to late 19th century.
 It replaced an existing Victorian Garden which had been built to celebrate the nation's Bicentennial in 1976.
White House Astronomy Night (and alternatively Astronomy Night on the National Mall) is an event first organized by the White House in conjunction with the Office of Science and Technology Policy to motivate interest in astronomy and science education.
 The original White House Astronomy Night was held in 2009 on the South Lawn.
 In 2010 the White House and the Office of Science and Technology Policy organized a similar event with help from Hofstra University, this time held on the National Mall.
 Between 2010 and 2014 annual events took place at the National Mall with coordination between Hofstra University and federal agencies including: the Smithsonian National Air and Space Museum, NASA, and the National Science Foundation.
 In 2015 an event took place in June at the National Mall, and then back at the White House again on October 19.
The S. Dillon Ripley Center, better known simply as the Ripley Center, is one of the buildings of the Smithsonian Institution series of museums located in the National Mall in Washington, D.C. The above-ground portion is only a small pagoda, and it descends into a larger underground portion.
 The Ripley Center houses the International Gallery, The Smithsonian Associates, and the offices of the Smithsonian Contributing Membership.
 It contains a conference center, an art gallery, and meeting/class rooms as well as exhibition space.
 It connects underground to the Arthur M. Sackler Gallery, the National Museum of African Art, and the Freer Gallery of Art.
Smithsonian is a side platformed Washington Metro station at the National Mall in Washington, D.C., United States.
 The station was opened on July 1, 1977, and is operated by the Washington Metropolitan Area Transit Authority (WMATA).
 It is a stop on the Blue, Orange and Silver Lines.
 The station's south entrance is at the southwest corner of Independence Avenue and 12th Street, Southwest, the street elevator is at the northwest corner of the same intersection, and the north entrance is on the south side of the Mall near Jefferson Drive, Southwest.
 The station is named for its proximity to the Smithsonian Institution's museums and is close to the Washington Monument, the Tidal Basin and other tourist attractions on and near the National Mall.
 The station is also near several federal office buildings, including those of the Department of Agriculture and the Department of Energy.
The Smithsonian Gardens, a division of the Smithsonian Institution, is responsible for the "landscapes, interiorscapes, and horticulture-related collections and exhibits", which serve as an outdoor extension of the Smithsonian's museums and learning spaces in Washington, D.C. Established in 1972 as a groundskeeping and horticulture program, Smithsonian Gardens currently manages 180 acres of gardens on the National Mall, 64,000 square feet of greenhouse production space, and the Archives of American Gardens, a research collection of over 60,000 photographs and archival records covering American landscape history from the 1870s to the present.
The National Museum of Natural History is a natural history museum administered by the Smithsonian Institution, located on the National Mall in Washington, D.C., United States.
 It has free admission and is open 364 days a year.
 In 2016, with 7.1 million visitors, it was the fourth most visited museum in the world, and the most visited natural history museum in the world .
 Opened in 1910, the museum on the National Mall was one of the first Smithsonian buildings constructed exclusively to hold the national collections and research facilities.
 The main building has an overall area of 1,500,000 ft2 with 325,000 ft2 of exhibition and public space and houses over 1,000 employees.
The Public Garden, also known as Boston Public Garden, is a large park in the heart of Boston, Massachusetts, adjacent to Boston Common.
 It is a part of the Emerald Necklace system of parks, and is bounded by Charles Street and Boston Common to the east, Beacon Street to the north, Arlington Street and Back Bay to the west, and Boylston Street to the south.
 The Public Garden was the first public botanical garden in America.
The National Mall is a national park in downtown Washington, D.C., the capital of the United States.
 The National Park Service (NPS) of the U.S. Department of the Interior administers the National Mall, which is part of its National Mall and Memorial Parks unit.
The Boston Common and Public Garden are a pair of public parks in Boston, Massachusetts.
 Boston Common, established 1634, is one of the oldest public spaces in the nation, and the adjacent Boston Public Garden is a more manicured garden space which was established in 1837 on marshland that was filled in.
 The two were listed as a single entry on the National Register of Historic Places in 1972.
 In 1987, the two were listed on the National Register separately, and each was also designated as a National Historic Landmark.
 The Boston Common, located east of the Public Garden, is separated by Charles Street.
The Friends of the Public Garden (FOPG) is a non-profit organization founded in 1970 for the protection and preservation of the Boston Common, Public Garden, and Commonwealth Avenue Mall.
 Located in Boston, Massachusetts, the Friends of the Public Garden works with the Boston Parks Department to care for the trees, sculptures, gardens, and grounds in the three parks.
 The organization is supported by a full-time staff, board of directors, council, volunteers, and over 2,500 members.
 The group aims to care for the Boston Common, Public Garden, and Commonwealth Avenue Mall so that the parks can be fully enjoyed by current and future locals and visitors.