Toronto Horticultural Society
Founded in 1834 under the patronage of Sir John Colborne, lieutenant-governor of Upper Canada (1828-36), this was the first horticultural society organized in this province. Established to encourage the introduction and cultivation of improved varieties of fruits, plants, and vegetables, its first president was the Honourable George Markland, inspector-general of Upper Canada. An oval of five acres was donated to the Society by the Honourable George W. Allan and on September 11, 1860 the Horticultural Gardens were opened by the Prince of Wales (Edward VII). Additional land was leased from the municipality of Toronto in 1864 and in 1888 this park was turned over to the city. It was named Allan Gardens in 1901.
Plaque via Alan L. Brown's site Toronto Plaques. Full page here.