The property includes a playground, off-leash dog park, and a 1,500 square metres (16,000 sq ft) conservatory with six greenhouses.

In 1864, the municipal government of Toronto acquired the lands surrounding the gardens, although it allowed the horticultural society to maintain it in return for permitting its public use.

[3][4] In 1855, Allan subdivided the land, although he retained a private garden north of Gerrard Street.

[4] In 1858, shortly after Allan's tenure as mayor had ended, he gifted the horticultural society 2.0 hectares (5 acres) of land for them to develop a garden,[3] although this transaction was not finalized until 1861.

[4] The Horticultural Gardens were opened to the public on 11 September 1860, with the Prince of Wales (later Edward VII) planting a maple tree in front of the pavilion.

[3] The original rustic wooden structures were replaced in 1879 with a new three-storey pavilion to be used for concerts, gala balls, conventions, and flower shows.

[3] Because the horticultural society was unable to cover its debts, the conservatory was later sold to the municipal government in 1888.

[4] In 1893, the National Council of Women of Canada was established inside the Horticultural Pavilion of the gardens.

An additional wing, which included three greenhouses, was built in 1956 and 1957 in order to expand the garden's exhibition space.

[1][4] During the 1960s, the property was enlarged, with the lands vacated by Jarvis Collegiate Institute absorbed by the park.

[1] The park was expanded again in 1990 after the city expropriated the Larry's Hideaway hotel along Carlton Street.

[4] A central oval with a drinking fountain that commemorates Graeme Mercer Adam was originally situated east of the Palm House; although this was later replaced with a pergola in 1995.