Located in Washington DC, the United States Botanical Gardens is one of the oldest botanic gardens in North America. Established in 1850, it has grown to house about 26,000 plants, including medicinal plants, orchids, and cacti.
The Conservatory, built in 1933, houses a jungle, desert, and primeval paradise.
Outdoors, the National Garden features a variety of mid-Atlantic plants.
The gardens are open 10-5 daily, including weekends and holidays. Admission is free.