The Botanic Gardens was established in 2005 to unite the gardens and programs of the Washington Park Arboretum, founded in 1934, and the Center for Urban Horticulture, opened in 1984. The Gardens are located around the shoreline of Union Bay on Lake Washington.
The City of Seattle owns the land and the University owns all of the trees and plant collections at the Washington Park Arboretum. In terms of care, maintenance and management, the City takes care of the park-like functions (trails, benches, garbage) while the UW Botanic Gardens takes care of the gardens, trees, and plant collections. The Japanese Garden is managed and maintained by the City with support of the Arboretum Foundation.
The University of Washington, the City of Seattle and the Arboretum Foundation are working together on the implementation of the Arboretum Master Plan. Examples projects are Japanese Garden Entry Structure, the Gateway to Chile, Cascadia Forest, New Zealand Forest and the Irrigation Mainline Project.