The Gardens Trust was formed by the merger of the Association of Gardens Trusts and the Garden History Society on 24 July 2015.

As a member of one of these founder organisations, namely the Association of Gardens Trusts, Avon Gardens Trust and its members are now affiliated to The Gardens Trust.

Over the years, both the Association of Gardens Trusts with its 36 county gardens trusts from all over England, and the Garden History Society have had the same aims of raising awareness of the designed landscape and protecting against inappropriate development through academic research, conservation initiatives and a dedicated volunteer base.

As the national voice for the county gardens trusts, The Gardens Trust shares information with a wide range of like-minded garden heritage groups including the Garden Museum, Parks and Gardens UK, the Historic Houses Association, the National Trust and Historic England.