Covering 200 acres, this arboretum, the highest-elevation research garden in the U.S., focuses on plants of the high desert, coniferous forests, and alpine tundra, all of which environments are found in the Flagstaff vicinity. On the grounds you can visit a butterfly garden, an herb garden, a shade garden, and a passive solar greenhouse. There are guided tours daily at 11am and 1pm, as well as regularly scheduled bird and wildflower walks.