In 1930, Dr. Walter P. Cottam, co-founder of the Nature Conservancy and chairman of the Botany Department at the University of Utah, began using campus land for plant research. For more than 30 years, he evaluated plants to determine their adaptability to their region.

In 1961, the Utah State Legislature formally recognized Cottam's impressive collection by designating the university's campus landscape as the State Arboretum. The original legislation mandated that the arboretum "provide resources and facilities for cultivating a greater knowledge and public appreciation for the trees and plants around us, as well as those growing in remote sections of the country and world."

With the growth of the arboretum, the University of Utah hired Richard Hildreth as a full-time director to initiate meaningful interpretation of the collections and to develop educational programs emphasizing practical horticulture and plant identification.

As the university grew, so did the arboretum's need for permanent public educational facilities and display gardens. In 1983, Ezekiel R. Dumke. Jr. and Richard Hildreth led the efforts to have the university dedicate 150 acres at the mouth of Red Butte Canyon for a regional botanical garden. The organization's name was changed from the State Arboretum to Red Butte Garden & Arboretum. The site provided an outstanding opportunity to showcase horticultural collections and to interpret the richly diverse natural area. This opportunity inspired the expansion of the garden's mission to include not only horticulture but also conservation and environmental education.

 Lagoon at Red Butte Garden, April 2006

The garden formally opened to the public in 1985. In 1994, the Walter P. Cottam Visitor Center (funded by the George S. and Dolores Dore Eccles Foundation) opened. Over the years other additions have been the Courtyard Garden, Fragrance Garden, Medicinal Garden, Herb Garden, Hemingway Four Seasons Garden, Dumke Floral Walk, Children's Garden, the Richard K. Hemingway Orangerie, an amphitheater, expanded gift shop, and the McCarthy Family Rose Garden. All were funded by community donations.