The present garden site was operated as an open pit mine from 1929 until 1956, producing over one million tons of crude diatomite. With declining production, the land was sold in 1957 to the County of Los Angeles for a sanitary landfill, which was in use until 1965. However, starting in 1961, an experiment in land reclamation began when County Board of Supervisors approved a motion establishing 87 acres (352,000 m²) as the site of the South Coast Botanic Garden, which was ultimately landscaped over 3.5 million tons of refuse, in a classic example of land recycling. The Sanitation District in cooperation with other County agencies carried out initial planning, grading and contouring. Operating responsibilities were given to the Los Angeles County Department of Arboreta and Botanic Gardens. In April 1961, the first large-scale planting took place on completed fill overlooking Rolling Hills Road, with over 40,000 plants donated by individuals, nurseries and the County Arboretum.
The site presents unusual difficulties in gardening. First, its soil is composed almost entirely of diatomaceous earth. Second, because of the diverse nature and thickness of the fill, settling rates vary throughout the garden resulting in frequent irrigation system breakage. Third, heat is caused by decomposition of organic matter below the soil surface, and it is accompanied by the production of gases, primarily carbon dioxide and methane.
A remake of the "Crying Indian" public service ad by Keep America Beautiful featuring the late Iron Eyes Cody was filmed at South Coast Botanical Gardens and it aired from 1975 to 78, where Cody was riding a horse instad of a canoe in the original version which was filmed in the San Francisco Bay area back in 1970. Here was the actual transcripts from the commercial, while Cody was on top of the hill looking at the freeway:
The first Americans love the land and the spirit remains true today! This is South Coast Botanical Gardens in California. Once a dump, community leaders clean and reclaimed it! However we got a long way to go! So get involved now! Write to Keep America Beautiful, 99 Park Avenue, New York! People start pollution, people can stop it (Cody showing a tear to the camera)!