The Garden's early mandate was to feature group exhibitions of existing work. This provided many artists with the opportunity to exhibit in an outdoor space and introduced the public to the many aesthetics of contemporary work. The first two exhibitions were selected by the Art Advisory Board with that mission in mind. The mandate shifted to existing works by one artist in the third exhibit by Louis Stokes and then to solo exhibitions of commissioned site specific work beginning with the fourth exhibit by Lee Paquette. The evolution in the mandate was influenced by several factors. It became quickly apparent that there was not an infinite number of existing works that would be suitable for outdoor display and that it would be difficult to continue large group shows for an indefinite period. Group shows also tended to focus the attention of the audience on the site rather than on the art, especially since the works were selected for formal rather than conceptual reasons and the exhibitions lacked curatorial focus. The greatest impact was the change, evidenced internationally, in the nature of sculpture, as it moved from being a point object on a pedestal to a work of many parts whose installation became a variable influenced by site and context. The majority of exhibitions in the Garden have been of solo artists creating new work specifically for the site, although guest curators have been invited by the Art Advisory Board, from time to time, to mount group shows of new or existing work.

The initial design for the Garden was conceived to accommodate the original mandate of group exhibitions of individual works. As the mandate shifted from group to solo exhibitions and/or installations, and as artists began to respond more directly to the site, the physical characteristics of the space were gradually simplified and altered. In time, gravel areas were replaced with grass, footings for pedestals were removed, concrete steps were eliminated and the site was re-graded. These changes provide a more neutral field for the work and allow greater flexibility for installations.