The Otari-Wilton's Bush Scenic Reserve was established in March 1906.
The Tourist and Health Department and then the Lands Department administered this reserve. In 1918 the enlarged reserve was transferred to Wellington City Council. Botanist Leonard Cockayne was closely associated with the establishment of the Otari Open Native Botanic Garden in 1926. Cockayne also instigated possum control at Otari in 1928. This was possibly the first systematic attempt to manage the pest on a reserve.