Mission of the Arboretum at Flagstaff is to increase the understanding, appreciation, and conservation of plants and plant communities native to the Colorado Plateau, to identify, evaluate, display, and introduce plants adaptable to the climatic and soil conditions of the Flagstaff environment, to seek through scientific research innovative solutions to conservation issues of this high altitude environment, and to develop educational programs that will increase the understanding of the need for wise stewardship of our natural environment.

History
Originally The Arboretum was the year-round home of Frances McAllister, built in the late 1960’s. In 1981 she began her long-held dream of creating an arboretum when she donated the land and created an endowment for the project. Her love of gardening actually goes back to her childhood experiences in her parents’ gardens in the Los Angeles area. But she found trying to duplicate the typical southern California garden in our high-desert climate frustrating indeed; increasingly she learned to appreciate the beauty and durability of our own drought-tolerant native plants in our area’s short growing season. The present gardens emphasize her desire to preserve and encourage the use of these water-wise natives in the gardens of our Colorado Plateau in a setting more akin to the terrain where they naturally occur.
The Arboretum’s 200 acres were originally a working ranch with cattle and full-time staff. The staff home, nearest the road along the property, was built first, followed by the main house, named after Walter Reichart, the architect, using the volcanic stone found on the property. The staff home has been converted to administrative offices, and Mrs. McAllister’s home serves many public functions, from dinners to lectures, meetings and conferences. The Horticulture Center—a large passive solar greenhouse—was subsequently added by Mrs. McAllister to aid numerous botanical projects in cooperation with Northern Arizona University’s faculty and students. The Log House, between the road and the meadow, was originally built on forested land in 1934-35 near old Route 66 just west of Flagstaff by Frances Burt and her fiancée John McAllister. This was their summer home for many years after they were married. The house was continuously lived in, but in recent years a business partnership that now owned the real estate determined that it should be demolished as land was cleared for other projects. To save it from "a fate worse than death", Mrs. McAllister hired a local contractor to move her house to The Arboretum, where it now serves as a summer home for interns and retreat for community members.
As The Arboretum has taken form through the years, several projects have been constructed to aid in the research and education components of our mission, including development of a nature trail, conversion of the original cattle tank to a pond for a study aimed at preserving the unique Little Colorado spinedace, a Constructed Wetlands to study how native plants are able to adapt to both extremes of wet and dry conditions, and expansion of greenhouse and bedhouse facilities.