The George Brown Botanic Gardens have significance as the site of major botanical and agricultural activity since 1886 for their association with the Holtze and Agostini families and with George Brown.
Maurice Holtze was appointed Government Gardener in 1878 and successfully curated the ‘Experimental Nursery’ and gardens first at a site near the Gaol at Fannie Bay and, after 1886, at the current site. Nicholas Holtze took over from his father in 1892 when Maurice became curator of the Adelaide Botanic Gardens. Their work demonstrated that a wide variety of plant species could be grown and flourish in the tropical north. Isidoro Agostini cultivated plants and worked at the Gardens between 1933 and his death in 1956. He spent significant time repairing and replanting after Army and bomb damage during World War II. George Brown, a council employee, was involved in management of the Gardens between 1957 and1990. He was Lord Mayor of Darwin from 1992 until his death in 2002. The Gardens have scientific significance because of the range of botanic specimens held there, and historic and social significance to the wider Darwin community.