Krohn Conservatory

Eden Park, on the hills above Cincinnati, has had municipal greenhouses since 1894. In the early 1930s those modest structures gave way to a more ambitious display house, completed in 1933 to designs by the local architects Rapp & Meacham. It was known at first simply as the Eden Park Greenhouse.

In 1937 it was renamed in honour of Irwin M. Krohn, who sat on Cincinnati's Board of Park Commissioners from 1912 to 1948.

A hailstorm in 1966 caused extensive damage to the glass. The restoration was entrusted to the greenhouse firm Lord & Burnham, which replaced the original wooden sashes with longer-lasting aluminium.

Run by the Cincinnati Park Board, the conservatory receives around 200,000 visitors a year. It also hosts receptions and weddings, and it appears in the 1993 film Airborne.

The Krohn Conservatory stands out for applying an Art Deco vocabulary, unusual for a glasshouse, to a Gothic-arch silhouette: the main hall has a pointed profile that gives it the air of a glass chapel, and some sources describe it as a blend of Gothic Revival and Art Deco.

The heart of the building is the Palm House, 45 feet (about 14 metres) high, where a 20-foot (roughly 6-metre) waterfall feeds a stream stocked with goldfish. Around it open themed rooms for tropical plants, desert plants, orchids, bonsai and seasonal floral displays.

Since the 1966 restoration, the glazing has been carried on aluminium sashes in place of the original timber ones.

The conservatory holds more than 3,500 plant species from around the world. The Palm House and the Tropical House show palms and rainforest vegetation around the waterfall, while the Desert Garden gathers cacti and succulents. The orchid display keeps about 75 orchids in bloom at any one time, drawn from a collection of thousands of plants spanning 17 genera. A bonsai collection, with regular demonstrations by the local bonsai society, and a floral display room that also grows citrus trees complete the sequence.

Seasonal shows follow one another through the year: a spring show, a butterfly show in the warmer months, an autumn show accompanied by a bonsai exhibition, and a holiday show. When the butterfly show closes, the butterflies are recorded and sent on to botanical gardens in Florida and Missouri.

The conservatory sits in Eden Park, a large hilltop park overlooking the Ohio River, close to the Cincinnati Art Museum, the Playhouse in the Park theatre and Mirror Lake, a reflecting pool created in the early 1960s on the site of a former reservoir. A flight of steps leads from the building to the Presidents' Grove, where trees have been planted in honour of American presidents since 1882.

About an hour is enough for the glasshouses. The butterfly show in spring and summer and the holiday show are the high points of the year.