The Horticultural Societies of Parkdale and Toronto were founded in 1987 and 1834 respectively, and were merged in 1988. The Toronto Society was the original donor of the land on which Allan Gardens now stands and, together with the Parkdale Society, continues a tradition of public beautification in central Toronto.

The Society is an affiliate of the Ontario Horticultural Association, and is a not-for-profit public service organization recognized by the Ministry of Agriculture.