Conceived in 1926 and opened in 1933, they were Australia's first national gardening project and were planned as a physical expression of the principle of cooperation between the Commonwealth and the States.

In horticultural terms the Gardens have provided the opportunity to exhibit the best varieties of Australian grown and overseas roses in a favourable climate.

[1] Parliamentary clerk Robert Broinowski played a key role in soliciting donations for the project, receiving plants from Canada, Japan, the Netherlands and the United States.

[1] Broinowski and Senate president Walter Kingsmill later successfully lobbied against an attempt by the Lyons government to build the National Library of Australia on a portion of the newly erected gardens.

[3] The gardens were also closely associated with Thomas Weston, the first officer in charge of afforestation in Canberra, whose ashes were scattered in the park he designed and laid out in front of the Parliament House.

Each garden is enclosed by a perimeter of large mature trees of a variety of non native species, evergreen and deciduous and arranged in a regular order.

The species used (basically cedar, oak, pine, plane and poplar) provide for a range of seasonal visual effects as well as wind protection and space definition.

Also along this avenue are mature poplar trees (Populus nigra) which were intended as markers, because of their strong vertical form and vivid yellow autumn colour, to key entry points within the Parliamentary Triangle.

This provides a bright green uniform ground plane which highlights the patterns created by light and shade and allows a smooth transition of views into adjacent spaces.