The United States Botanic Garden, Washington, DC

The United States Botanic Garden is the oldest continuously operating botanic garden in the United States, and it predates nearly everything else on the National Mall. It was established by Congress in 1820 — more than two decades before the Smithsonian Institution opened its doors, and before the Washington Monument was even begun. The idea was older still. In 1816, the Columbian Institute for the Promotion of Arts and Sciences, a learned society in the young capital, proposed creating a botanic garden to collect, grow, and distribute plants "of this and other countries that might contribute to the welfare of the American people." George Washington himself had suggested a place for a botanic garden in Pierre Charles L'Enfant's plan for the capital, and on May 8, 1820, President James Madison signed the bill granting the garden five acres of land at the base of the Capitol.

The first garden stood west of the Capitol, on ground stretching from First Street to Third Street between Pennsylvania and Maryland Avenues — roughly where the Capitol Reflecting Pool lies today. The land was swampy, and members of the Columbian Institute drained it and set out to collect plants and seeds. For seventeen years the garden grew ornamental and useful plants — food and medicinal species alongside curiosities — tended by a society of gentlemen scientists who believed a young republic needed its own living library of the plant kingdom.

Then the society faltered. In 1837 the Columbian Institute stopped holding meetings, and the garden ceased to function. Its plants were scattered, its grounds neglected, and the idea of a national botanic garden might have died there — a footnote in the capital's early history. What saved it was a voyage.

In 1838, Lieutenant Charles Wilkes set out from Norfolk, Virginia, in command of the United States Exploring Expedition — a four-year, round-the-world naval voyage commissioned by Congress to survey the Pacific, chart unknown coasts, and bring home scientific specimens. The expedition was a costly, dangerous undertaking: Wilkes returned in June 1842 two ships poorer, with nearly twenty men dead and more than 87,000 miles sailed. But he also returned with the first definitive proof that Antarctica was a continent, with thousands of cultural artifacts, and with some 10,000 plant specimens and hundreds of living plants gathered in the South Pacific and around the globe — many of them species never before seen in the United States.

Congress needed somewhere to put the living plants, and the idea of a national botanic garden was resurrected. The collection was entrusted to the horticulturist William Brackenridge, who had sailed with Wilkes and kept the plants alive on the long voyage home in wardian cases — sealed glass boxes that were, in effect, the first portable greenhouses. A small Gothic greenhouse was built, and under Brackenridge's care the plants flourished. In 1850 the garden was moved back to the foot of the Capitol, on the same ground the Columbian Institute had worked, and a Victorian Conservatory opened to the public. The garden has been publicly accessible ever since. In 1856 the collections were formally named the United States Botanic Garden, placed under the jurisdiction of the Joint Committee on the Library of Congress.

The Wilkes plants are the founding collection, and their descendants still shape the garden. The expedition's specimens established a pattern that continues today: the garden collects plants from around the world, grows them, studies them, and shares them — a living museum whose exhibits breathe, bloom, and occasionally, famously, stink.

The garden's history is a history of being moved. The first garden died in 1837; the second was reborn from the Wilkes collection; and the third move came in the twentieth century, when the Mall itself was remade. In 1902 the Senate Park Commission's McMillan Plan proposed clearing the Victorian landscaping from the National Mall to restore an unobstructed vista between the Capitol and the Washington Monument. The Botanic Garden was the last institution moved off the Mall, in 1924 — shifted only a few hundred feet south, to the triangle of land bordered by Maryland Avenue on the north, First Street on the east, Independence Avenue on the south, and Third Street on the west.

The new home was worth the move. In 1933 the garden reopened in a new Conservatory, a 30,000-square-foot Lord & Burnham greenhouse that was, at the time of construction, the largest aluminum building in the United States. Its glass dome and limestone base still anchor the eastern end of the Mall, just southwest of the Capitol, and the building in use today is that 1933 Conservatory — renovated, restored, and still doing the job it was built for. Since 1934 the Architect of the Capitol has served as the garden's acting director, a reminder that this is not a city park but an institution of the federal government, tended by the same office that cares for the Capitol itself.

The Conservatory closed for a major renovation on September 1, 1997, and reopened on December 11, 2001, its glass and steel restored and its plant rooms rebuilt for a new century. It was the garden's fourth great transformation — and, so far, its last.

Step through the doors on Maryland Avenue and the Mall disappears. The Conservatory is divided into separate rooms, each simulating a different habitat, each monitored by computer-operated sensors that hold the temperature and humidity its plants demand. The largest is the Jungle, a multi-story rainforest room where a second-story catwalk lets you look down on the canopy as well as up through it — palms and tropical trees rising toward the glass roof, the air warm and heavy even in a Washington winter.

The Orchid House holds a rotating display drawn from the garden's orchid collection, one of the finest in the country: hundreds of blooming plants at any given time, from the familiar moth orchids of the florist's shop to strange, waxy species collected in the wild. Nearby, the Garden Primeval recreates the world before flowers existed, with ferns, cycads, and other ancient lineages that have survived hundreds of millions of years. The World Deserts room is its opposite — cacti and succulents from the driest places on Earth, spiny and sculptural, thriving on neglect. The Medicinal Plants room shows the species behind the pharmacy: the plants that gave us aspirin, quinine, and morphine, among others. The Rare and Endangered Plants room holds species that may no longer exist in the wild at all, kept alive here as a last refuge. And the Children's Garden, with plants chosen to invite touch and curiosity, is where the garden makes its next generation of converts.

Every room is a working exhibit, not a static display. Plants are swapped in and out as they bloom, and the garden's staff propagates and studies them behind the scenes at its Production Facility in Southwest Washington. The corpse flower — the titan arum, whose rare bloom smells famously of rotting meat — has drawn crowds here that spill out onto Maryland Avenue, a reminder that a plant collection can still stop a city in its tracks.

West of the Conservatory, across the garden's three acres of outdoor grounds, lies the newest part of the institution: the National Garden, which opened on October 1, 2006. It was built to celebrate the plants of the Mid-Atlantic, and its centerpiece is the Regional Garden, a landscape of species native to the Atlantic Coastal Plain and the Piedmont — the plants that grew here before the city did, arranged as they grow in the wild.

Around it are the garden's outdoor rooms: a Rose Garden; a Butterfly Garden, planted to feed and shelter pollinators, with a bronze butterfly sundial at its heart; the First Ladies Water Garden, a water garden honoring the First Ladies of the United States; a Lawn Terrace; and an amphitheater for concerts and programs. The National Garden was funded by the National Fund for the U.S. Botanic Garden, the garden's friends group, and it changed the institution's public face: the garden is no longer only a greenhouse to step into, but a landscape to wander through, with the Capitol dome rising over the trees at every turn.

Across Independence Avenue, south of the Conservatory, lies Bartholdi Park — and at its center stands one of the most extraordinary objects in Washington: the Bartholdi Fountain, formally the Fountain of Light and Water. It was designed by Frédéric Auguste Bartholdi, the French sculptor who would later create the Statue of Liberty, and built for the 1876 Centennial Exposition in Philadelphia, where it stood near the entrance to the fairgrounds celebrating the hundredth birthday of the Declaration of Independence.

The fountain is cast iron, painted to look like bronze, and it is enormous: thirty feet tall, weighing more than fifteen tons, its great basin held aloft by three colossal caryatids eleven feet high, ringed with lamps modeled on Paris streetlights and crowded with tritons, fish, and turtles. Cast in Paris by the Durenne foundry, it was too grand — and too expensive — to sell after the exposition closed. Congress bought it in 1877 for $6,000, half its asking price, at the suggestion of Frederick Law Olmsted, the landscape architect then redesigning the Capitol Grounds. It was placed at the base of Capitol Hill, on what was then Botanic Garden ground.

The fountain was dismantled in 1927, when the garden was moved off the Mall, and stored until 1932, when it was re-erected in its present location, in a two-acre park created for it across Independence Avenue. The park was officially named for its fountain in 1985. In 2008 the Architect of the Capitol began a complete restoration — the first full deconstruction of the fountain since 1927 — and it returned to Bartholdi Park in May 2011, its lamps rebuilt to replicate the original gas fixtures. Today the park around it is a demonstration garden, a collection of small, structured plantings meant to give home gardeners ideas to take home — the working end of the garden's mission, in the shadow of its most theatrical object.

The United States Botanic Garden is a museum in the truest sense: accredited by the American Alliance of Museums, holding a collection of living things that cannot be stored in a vault or hung on a wall. More than a million people visit each year, and the garden's mission has not changed since 1816 — to inspire people to appreciate, study, and conserve plants, and to show how plants underpin everything from food and medicine to the air of the city itself.

Its place on the Mall is part of the point. The garden sits at the foot of the Capitol, between the legislative branch and the Smithsonian museums, and it belongs to both worlds: a scientific institution and a public pleasure ground, a place where schoolchildren press their noses to orchids and botanists study species that exist nowhere else on Earth. It has survived the death of its founding society, a four-year naval expedition, three relocations, and a century of Mall redesigns — and it is still here, still free, still growing.

The Conservatory entrance is at 100 Maryland Avenue SW, at the foot of Capitol Hill on the eastern end of the National Mall — a short walk from the Capitol, the Library of Congress, and the Smithsonian museums. The easiest way to arrive is by Metrorail: take the Blue, Orange, or Silver line to Federal Center SW, then walk north along Third Street SW and east to Maryland Avenue, where the glass dome of the Conservatory comes into view. The National Garden is adjacent to the Conservatory, with entrances from Independence Avenue, from Maryland Avenue at Third Street, and from the Conservatory Terrace; Bartholdi Park lies just across Independence Avenue to the south.

No fixed ticket price or opening hour is stated as fact in this article: the Conservatory is typically open 10 a.m. to 5 p.m. daily, including weekends and most holidays, and is closed on December 25, but hours can change — check the official U.S. Botanic Garden site (usbg.gov) before visiting for current hours and any special closures. Admission is free. Allow at least an hour for the Conservatory alone, and another hour for the National Garden and Bartholdi Park; the garden rewards a slow pace, and the best route is to start in the Jungle while the light is good, linger in the Orchid House, and finish outside, walking the National Garden with the Capitol dome behind you.

Address: 100 Maryland Avenue SW, Washington, DC 20001 (Conservatory entrance on Maryland Avenue).

Transit: Metrorail Blue, Orange, or Silver line to Federal Center SW, then walk north on Third Street SW and east to Maryland Avenue; the Conservatory's glass dome is visible from the station walk. Metrobus serves Maryland Avenue and Independence Avenue SW.

Hours/Admission: No fixed ticket price or opening hour is stated as fact in this article. The Conservatory is typically open 10 a.m. to 5 p.m. daily, including weekends and most holidays, and closed on December 25, per the garden's official site — check usbg.gov before visiting for current hours and any special closures. Admission is free.

Best timing: Allow at least two hours: an hour inside the Conservatory and an hour for the National Garden and Bartholdi Park. Start in the Jungle, linger in the Orchid House, and finish outdoors in the National Garden with the Capitol dome behind you. The Conservatory is a warm, humid refuge in winter and a cool, shaded one in summer.