The Arboretum at Flagstaff was founded by Frances McAllister in 1981 as a private nonprofit organization under the official name “The Transition Zone Horticultural Institute.” While research was the original primary focus, over the years it has become known as a destination for local and out-of-town visitors who want to learn more about the native plants and animals found in northern Arizona, and as a wonderful venue for a wide variety of events and educational programs.


The Arboretum at Flagstaffs mission is to increase the understanding, appreciation, and conservation of plants and plant communities native to the Colorado Plateau. We strive to:

  • Identify, evaluate, display, and introduce plants adaptable to the climatic and soil conditions of the Flagstaff environment
  • Seek through scientific research innovative solutions to conservation issues of this high altitude environment
  • Develop educational programs that increase the understanding of the need for wise stewardship of our natural environment.

A Brief History of The Arboretum and Founder Frances McAllister

The gardens and buildings were the residence of The Arboretum’s founder, Frances McAllister, who first came to Flagstaff while she was passing through on the train in the 1930s. She was given a parcel of land in Flagstaff and a rustic cabin as a wedding gift by her husband John Vickers McAllister. Frances and her family traveled from Los Angeles every summer to spend time in their cabin with a marvelous vista of the San Francisco Peaks.

After her husband’s passing, Frances moved to Flagstaff permanently in 1967. She purchased the property that is the current site of The Arboretum and constructed a residence designed by the architect Walter Reichardt. Frances’ love of native plants began as a small child and she pursued her passion for gardening in her new home. She found that gardening at 7,000 feet is more challenging than in the temperate climate of L.A. She had more success with native species and adapted exotic plants from other high, dry locations. Her experimentations and success in gardening prompted her to want to share her gardens and research with the public.