In 1858, prominent local politician George Allan offered the Toronto Horticultural Society a five-acre parcel of land to develop a garden. The first public structure in the Park was a rustic pavilion built in 1860. In 1864, the City of Toronto purchased the surrounding lands from Mr. Allan, which it then re-leased to the Horticultural Society on the condition that the grounds be publicly accessible and free of charge.
In 1879 the Society opened a new Horticultural Pavilion between Carlton and Gerrard Streets. Designed by the architectural firm of Langley, Langley and Burke, this impressive 75’ x 120’ wood, iron and glass structure was later expanded with a 45’ x 48’ conservatory on the south side. One of the finest facilities of its type in all of Canada, the new building was in constant demand for promenade concerts, gala balls, conventions and flower shows. Despite the park's increasing popularity, debt forced the Society to sell its interest in the park and surrounding lands to the City in 1888.
The City initiated a program of improvement and expansion. In 1894 it replaced the old conservatory with a more spacious 90’ x 61’ facility. In tribute to the accomplishments and memory of George Allan, it was renamed Allan Gardens shortly after his death in 1901. In 1902, the Toronto Burns Monument Committee presented the City with a life-sized statue of Scottish poet Robert Burns, which still stands at the east end of the park.
A disastrous fire on June 6,1902 destroyed the Horticultural Pavilion and parts of the conservatory. City architect Robert McCallum designed its replacement, the classically proportioned domed Palm House which opened in 1910 and stands on the site today. The 1920’s saw two new display greenhouses added to the north and south ends of the Palm House. The City rejuvenated the park from 1956 to 1963. With new lands acquired along Jarvis and Carlton, the total site grew to almost 13 acres. In 1957, it constructed additional greenhouse wings to expand conservatory display space and reconstructed the adjacent garden areas.
The latest addition to the site is the Children’s Conservatory. This greenhouse belonged to the University of Toronto Botany Department and was built in 1932. The University donated the historic greenhouse, which was moved from its location at College and University Avenue and attached to the existing conservatory at Allan Gardens. It was officially re-opened in 2004. The Children’s Conservatory is closed to the public, but offers horticultural programs for children.
Today, Allan Gardens Conservatory greenhouses comprise over 16,000 square feet. It boasts an extensive permanent collection that is supplemented by colourful seasonal plants and flower shows.