Boyce Thompson Arboretum

Superior, Arizona, United States

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The Boyce Thompson Arboretum in Superior, Arizona, founded in 1924 by mining magnate William Boyce Thompson, is the oldest and largest botanical garden in the state and one of the earliest dedicated to arid plant species in the United States.

Spanning 392 acres, the arboretum sits along Queen Creek beneath Picketpost Mountain and was designed as both a research facility and a living museum showcasing desert flora from around the world. The site includes visitor amenities such as a center, greenhouses, demonstration and herb gardens, and a 1.5-mile trail through diverse ecological displays including cacti, palms, eucalyptus, and plants from Australia and South America.

It became Arizona’s first nonprofit research organization in 1927 and opened to the public in 1929. Despite financial struggles during the Great Depression, it continued to grow under successive directors, adding specialized gardens and conservation programs.

The arboretum is recognized for its role in botanical research, education, and conservation, maintaining rare plant collections, partnerships with universities and parks, and hosting community programs while providing a scenic desert habitat for visitors year-round.