Living history: UArizona’s Campus Arboretum celebrates its 20th anniversary

Jan. 23, 2023
The historic Krutch Garden of Southwest native cacti and succulents in the foreground frames Old Main.

Perhaps one of the most overlooked yet extraordinary gardens within the Arboretum collection is the Historic Joseph Wood Krutch Garden. This garden, filled with Sonoran native species, once covered half of what is now the UA mall.

Maria Luz Roja

Tanya Quist poses in front of catclaw vines behind the Forbes Building on the University of Arizona main campus.

Tanya Quist, director of the University of Arizona Campus Arboretum.

When Tanya Quist takes in the botanical riches found on the University of Arizona campus, she sees more than fascinating trees, flowers, succulents, and cacti.

She sees a global impact.

“The Campus Arboretum is a product of our land-grant mission,” said Quist, Director of the University of Arizona Campus Arboretum and an associate professor in the School of Plant Sciences. “It’s a product of this powerful concept that land-grant schools embody, that we provide education and research and, importantly, we do outreach. Outreach transforms our education and research into assets for the communities of our state and beyond.”

This fall, the Campus Arboretum celebrates its 20th anniversary. The celebrations – special tours, exhibits, and more – coincide with its formal designation 20 years ago as a place where species are collected, protected, and preserved.

The 1st building at the University of Arizona (Old Main) being constructed in the middle of the desert. The city of Tucson is in the background. The photo is Looking west.

The first building at the University of Arizona (Old Main) being constructed in the middle of the desert. The city of Tucson is in the background. The photo is looking West.

University of Arizona Special Collections

But the origins of the arboretum, which includes all plants growing on the 400-acre main campus, date to the University of Arizona’s founding as the state’s land-grant college in 1885.

From its beginnings, the arboretum has served as something of an experiment ground, a place where faculty and researchers could test what could survive in the desert Southwest, Quist explained. It continues to serve as an outdoor laboratory where researchers can answer questions about sustainability.

Quist said she is proud of the arboretum’s past and even more excited about its future. “What we learn and do here has applications in building resilient cities around the world who are about to experience some of these same challenges.

“Beyond conservation of individual specimens, the arboretum was intended to promote stewardship and preservation of natural resources through management practices, better tree selection, and making the lessons of the past more apparent. Every square inch of this space we inhabit has the potential to inform, to inspire.”

Digging into its roots

A photo shows a narrow path lined with citrus trees

The citrus walk or orange arbor between Gila and Maricopa
Residence Halls is one of the campus’ most unique land-

University of Arizona Campus Arboretum

In the early days, research focused on agricultural commodity crops, like cotton and citrus, as faculty sought ways to provide an economic boost to the territory, before Arizona was even a state.

For instance, Robert Forbes, an early dean of the College of Agriculture, traveled around the world and brought back various cultivars of olive trees, planting them on campus to test which ones might survive, and even thrive. These trees can still be found on campus, although their success as a cash crop didn’t necessarily pan out.

But Forbes’ impact can be found in something else: He created what landscapers call allées, or avenues, of trees lining sidewalks and streets, especially from Old Main to the western edge of campus. It brought a formality to the University of Arizona campus.

“It was another step toward establishing the main campus as a public space, as a public garden,” Quist said.

As more people moved to Tucson and into Arizona – and awareness of our limited resources, especially water, grew – the focus of agricultural research and the arboretum shifted. By the mid-century, faculty turned from researching commodity crops to studying trees and plants that could be introduced here without breaking the bank.

“The goal was to find landscape ornamentals that would allow us not only to build urban green spaces that beautify and enhance the human experience but that contribute to environmental health.” Quist said. “Greenspaces, especially trees, are essential to our health as a planet and as a society.”

Color photograph of cactus within the Joseph Wood Krutch Memorial garden, including two boojum trees.

Cactus within the Joseph Wood Krutch Memorial garden, including two boojum trees.

University of Arizona Special Collections

Palm trees were brought in, along with exotic species from around the globe: silk floss tree, carob, boojum, monk’s pepper, and many, many more. Quist said the criteria was fairly simple: Figure out what can survive on roughly 11 inches of precipitation a year and can withstand the semi-arid climate.

She said there is a great benefit in having that diversity on campus, for educational, research, and ecological reasons. Diversity promotes greater resiliency in the environment; if one species struggles, others pick up the slack.

And while some people may wonder if the most “natural” setting would be to have only plants that are native to the Sonoran Desert, Quist agrees but adds that the built environment sometimes may require a broader plant palette.

“The natural setting of the Sonoran Desert didn’t have an urban heat island, for example,” she said. “With a more diverse palette of plants, we may have a better chance of fitting the right plant to the location and allow the plant to perform well and offset some of the environmental impact cities introduced.”

A manifesto for trees

These days, the Campus Arboretum has entered a phase where it takes the lessons of the past, combined with current research, to help determine what will work in the future.

“Technically, if we only wanted a green space, we could plant anything, but we are an educational institution with the expertise and the responsibility to do better,” Quist said. “The arboretum provides curation, standards and guidance for selecting plants and developing landscapes in a way that creates educational opportunities, supports research, and inspires the community.”

What does that look like in practice? Quist points to the gardens around the USS Arizona Memorial on the campus mall.

Originally, planters around the memorial were filled with flowering annuals. The flowers are perfectly appropriate for a memorial, she noted, but they required numerous resources, or inputs: the labor and cost of replanting every four months, fertilizer, pesticides, and a lot of water just to produce occasional splashes of color.

So, the Campus Arboretum looked for a creative alternative, one that would both honor the people who lost their lives on the USS Arizona and promote the arboretum’s mission.

“The Campus Arboretum raised funds and installed cacti and succulents that resemble coral reef,” Quist said. “The new plants are perennials, so they don’t need to be ripped out and replaced regularly. Now we have a customized and unique memorial that also provides diversity, interest, and inspiration. Ultimately, it models a more sustainable way – reducing inputs and maximizing benefits.”

Those benefits, or ecosystem services as they are called, are integral to what the Campus Arboretum is trying to demonstrate and they illustrate the importance of its formal designation 20 years ago.

“The Campus Arboretum’s goal is to build a landscape that is efficient, that uses very little inputs or resources but that provides significant outputs. The important lesson is that trees matter.”

Historically, only a relatively small percentage of U.S. campuses have an arboretum. Even fewer were integrated into the campus the way the University of Arizona’s is, Quist explained.

“We are ahead of the curve and proud of what we’ve been able to accomplish here.”

Where is the Campus Arboretum?

Here’s a simple trick to finding the University of Arizona Campus Arboretum: Stand almost anywhere on campus, look about, and you’ve found it. That’s because the arboretum is not a specific site but instead includes all the plants growing on the 400-acre main campus.

Click here for an interactive map of the University of Arizona Campus Arboretum that allows you to learn more about trees and other plants, based on your location on campus.

Anniversary events

For additional information about the Campus Arboretum, including tours and special 20th anniversary events, visit