Onsilium Greenhouse Café (온실리움), Ulju

Onsilium (온실리움) stands in Sangbuk township, Ulju County (Ulsan), on lot 1112 and three others. According to the private-garden register of the Korea Arboreta and Gardens Institute, the name joins 온실, "greenhouse", to the suffix -rium used for exhibition places, and the garden was designed by landscape architect 최신현, head of the firm 시토포스, around the theme of the greenhouse, to embrace the surrounding landscape, light, wind, trees and flowers. The same register gives a registration date of 21 December 2018; Yonhap states that the garden was designated that year as the city's first private garden.

The status of "private garden" (민간정원) covers a garden kept up by an individual or an organisation and open to the public. Onsilium has since been singled out: in October 2024 the Korea Forest Service ranked it among the country's 30 most beautiful private gardens, in the category of unusual gardens, for its tropical trees and bonsai; in February 2026 Ohmynews reported that it had been selected for the Minister of Agriculture's award, presented as a first for a private garden, in recognition of its contribution to garden policy and culture.

The place is described as a glass greenhouse (유리온실) that doubles as a café (온실카페). A blog of March 2025 writes that the whole café is under glass, with careful heating for the tropical plants. The Ulju County blog (28 January 2026) details the building: one enters through the café, which has three spaces around the counter; a staircase goes down to an elongated space opening onto the greenhouse through large windows, then to the greenhouse itself, where tall trees grow. It is heated in winter and the air is humid.

The 8,143 m² garden (7,351 m² of it green space) includes, according to the register, a traditional garden, a cultural garden and a botanical garden, an outdoor terrace, plantings on the roof, parking, toilets, visitor-activity facilities and a rest room; Yonhap mentions an English-style garden. Outside, a second greenhouse is used for growing plants, mostly herbs, and drinks are not allowed there, according to the 2025 blog.

For the greenhouse café, the official register cites Washington palms (워싱턴야자), cacti of all kinds, warm-temperate species native to Jeju and judged of high conservation value (제주 팽나무, 아그배나무, 제주 참꽃), old Korean trees, and pampas and other ornamental grasses from European gardens. In all it counts more than 180 species and about 4,500 plants. No Latin names are given.

The Ulju County blog and the 2024 and 2026 press report tropical trees and a baobab growing under glass; a March 2025 blog speaks of a small baobab, palms and many cacti. The 2024 press adds bonsai. The 2025 blog regrets that most plants are not labelled.

Onsilium is a garden-café: the Ulju County blog specifies that one must order one drink per person to enter the building. That blog presents it as a place to enjoy plants even in winter, thanks to the heated greenhouse; the outdoor garden suits a stroll.

Allow time for a coffee and a walk in the garden. It is worth checking the opening hours before the trip. The register entry links, as related sites, to the Yeongnam Alps leisure centre (the cave), the Sinbulsan waterfall recreation forest and Ganjeolgot park, known for its sunrise.