Tamanegi House, Fukui Prefectural General Green Center (福井県総合グリーンセンター)

The greenhouse belongs to the Fukui Prefectural General Green Center at Maruoka (Sakai city). According to the official timeline, the centre grew out of the prefecture's "Green" policy: works began in 1975, the flower centre opened in October 1977 and the greening centre in October 1978, and the three bodies (forestry station, greening centre, flower centre) merged in April 1980 as the General Green Center. In October 1980 the urban botanical garden, where the greenhouse stands, and the green consultation centre were completed; the same month the site hosted the 4th National Tree-Nurturing Festival in the presence of the crown prince and his wife, according to the Japanese Wikipedia. The neighbouring Green Park only opened in 1992.

The greenhouse stands in this garden. The official site states that it showed tropical plants until 2015 and that in October 2015 the display changed from tropical plants to flowers. The Japanese Wikipedia, which relies on the same official page, still mentions tropical plants alongside seasonal flowers, and OpenStreetMap still names the building a "tropical display greenhouse": these wordings seem to predate the 2015 change.

The official site speaks of a "dome-shaped greenhouse" nicknamed Tamanegi House, the "onion house", without giving a construction date, architect, floor area or height, and without saying what the envelope is made of. The glazing is visible in a Wikimedia Commons photograph taken in November 2015: a bulbous dome ending in a point, entirely clad in glass panels carried by a network of metal members, with a green-painted entrance porch at the foot of the shell.

The official site dates the installation of a wood-pellet boiler to March 2008, and the page devoted to that boiler, updated in October 2016, says it supplies heat to the flower display greenhouse and to a flower-growing greenhouse; the pellets come from local sawmill waste and thinnings. The rules on the official page forbid entering with pets, even carried or in a pushchair, and eating or drinking inside.

Until 2015 the greenhouse showed tropical plants; in October 2015, according to the official timeline, the display changed from tropical plants to flowers, which gives it its present name of "flower display greenhouse". Since then the settings follow the calendar: the Fukui city tourism site speaks of a "tropical flower field" inside and lists Halloween and Christmas among the seasonal themes.

Since 9 September 2026 the greenhouse has been a "Halloween Garden", with two original characters, a pumpkin cat and a pumpkin man, and autumn flowers: ornamental peppers, cockscombs, asters, dahlias, nobotan and others.

The urban botanical garden around it holds about 1,000 species and 50,000 trees, including foreign, medicinal, aromatic and local species; the Green Park has 154 species and about 25,000 trees.

The dome stands in the 10-hectare urban botanical garden, among lawns and a fountain. Nearby are the green and flower consultation centre, a moss gallery (about 40 species, bonsai and moss terrariums) and the bonsai exhibition, open from 1 April to 20 November. On the other side, the 8.2-hectare Green Park holds Woodream Fukui, an exhibition hall on the prefecture's forests with a viewing deck, and Wood House Kuzuryu, which shows kitamaebune ships and a mechanical clock.

The site can be reached by Keifuku bus from JR Fukui station (stop "Green Center-mae") or by car, about fifteen minutes from the Fukui-Kita exit of the Hokuriku Expressway. The display changes with the seasons; in 2026, autumn is Halloween.