Anna Scripps Whitcomb Conservatory

Work on the Belle Isle conservatory began in 1902 on the 982-acre island park that Detroit maintains in the middle of the Detroit River. Designed by architects George D. Mason and Albert Kahn, it opened on 18 August 1904 as the "Horticultural Building" and quickly drew crowds: by the mid-1920s it was averaging 1.5 million visitors a year.

The central dome's original timber frame was replaced by a metal one in the mid-twentieth century, in 1949 or 1953, at a cost of about $500,000. On 6 April 1955 the building was dedicated to Anna Scripps Whitcomb, who had just given the city her collection of 600 orchids. The Show House was remodelled in 1981.

Institutional sources describe it as the oldest continually operating conservatory in the United States. After a first phase of work begun in 2019 ($2.5 million, including $1 million from the Ralph C. Wilson Jr. Foundation), the building closed for two years for a $10 million restoration, funded with $7.5 million in federal COVID-19 relief money and a $2.5 million private gift channelled through the Belle Isle Conservancy. It reopened on 4 December 2024 and is managed by the Michigan Department of Natural Resources (DNR).

The layout follows the great European glass palaces, with London's Crystal Palace and the Palm House at Kew cited as models. At its centre stands the Palm House beneath a dome given as 85 feet (about 26 m) high by the conservatory, though the DNR describes it as an 80-foot dome. Wings radiate from it: the south wing holds the Tropical House, the north wing the Cactus House and the Fernery, and the east wing the Show House. The Fernery is sunk below grade, which keeps it cooler and more humid.

The restoration completed in 2024 focused on the upper 60 feet of the dome: more than 1,500 panes were replaced with laminated glass, asbestos and lead paint were removed, the steel trusses repaired, and new catwalks and irrigation installed. The work also covered the exterior limestone panels, the Show House floor and planter walls, the vestibule, and the glazing of the tropical and cactus houses. The building sits on about one acre within a 13-acre site, with some twenty production greenhouses to the east.

More than 2,000 plants from around the world are grouped into five settings. Under the dome, the Palm House holds palms and tropical trees; specimens that eventually reach the glass have to be removed. The Tropical House emphasises food plants such as bananas, oranges and figs. Cacti and succulents have a house of their own, the Fernery is given over to ferns, and the Show House hosts seasonal flowering displays.

The conservatory is best known for its orchids. Anna Scripps Whitcomb's 1955 gift comprised 600 rare specimens, many of them brought out of Britain for safekeeping during the Second World War, and the collection is described as one of the largest municipally owned orchid collections in the United States. Orchid and poinsettia shows are held in season.

The conservatory stands at the heart of Belle Isle, next to the Belle Isle Aquarium. Entry to the building is free, although driving onto the island, a Michigan state park, requires a Recreation Passport. Outside, the formal gardens, the lily and koi pond laid out in 1936, the Levi Barbour Memorial Fountain, a Japanese lantern given by the city of Toyota in 1985 and a peacock sundial installed in 1927 extend the walk. An hour is enough for the five houses; the seasonal displays and the orchid and poinsettia shows make it a good winter outing.