This 100-year-old Arizona garden grows desert plants from six continents at a mountain’s base

It’s been here since 1924

About an hour east of Phoenix, where the Sonoran Desert meets the base of Picketpost Mountain, 372 acres of cultivated gardens and wild desert terrain run along Queen Creek.

Boyce Thompson Arboretum holds over 4,000 types of plants pulled from dry lands across the globe, and it has been doing this longer than almost any botanical garden west of the Mississippi.

Five miles of trails wind through 12 garden areas, and what you find around each bend comes from a different continent.

A copper magnate’s Red Cross trip changed everything

William Boyce Thompson made his fortune in copper.

Born in Virginia City, Mont., in 1869, he built companies like Magma Copper Company in Superior and Newmont Mining Corporation. But a 1917 Red Cross mission to Russia during the revolution changed the way he saw the world.

He watched how deeply people depended on plants, and that trip pushed him to create both this arboretum and the Boyce Thompson Institute for Plant Research, now part of Cornell University.

The arboretum opened to the public on April 6, 1929.

Plants from Australia, Madagascar and the Arabian Peninsula

You walk past species from Mexico, India, China, Japan, Israel, South America, the Mediterranean and Africa, all growing in the same Arizona desert.

The arboretum holds three nationally accredited collections recognized by the American Public Gardens Association: eucalyptus trees, desert legumes and southwestern oaks.

Mixed into all of it are rare and endangered species that most people will never see anywhere else. The whole place feels like a world tour on foot.

A 117-foot eucalyptus they call Mr. Big

The Australian exhibit covers about 10 acres and holds the largest, most diverse stand of eucalyptus trees in North America, with 93 types in the collection.

At the center of it stands Mr. Big, a red gum eucalyptus that arrived from Australia in 1926 as a six-foot sapling. Today he rises about 117 feet with a circumference of more than 22 feet.

He carries the title of Champion Tree and ranks among the largest of his species in the country.

A cactus discovered right here and named for the garden

In 1926, botanist Charles Russell Orcutt found a hedgehog cactus growing on the arboretum grounds that no one had ever described before. He named it Echinocereus boyce-thompsonii after the garden and its founder.

If you visit in late March or early April, you can spot its pink-magenta flowers along the trails in the cactus garden.

The species is relatively rare, so catching it in bloom here is one of those things you time a trip around.

Nearly 5,870 plants moved 75 miles by semitruck

In December 2015, crews started loading nearly 5,870 mature desert plants onto semitrucks in Scottsdale, packing them into custom-built wooden boxes for a 75-mile ride to the arboretum. Some of those plants stood 25 feet tall.

The collection belonged to H.B. Wallace, whose father, Henry A. Wallace, served as the 33rd Vice President of the United States.

Five years of work later, the 13-acre Wallace Desert Garden opened in 2020, adding 1.5 miles of trails, two water crossings and over 860 new species.

Over 270 bird species and the occasional bobcat

The Audubon Society designated this place an Important Bird Area, and the count sits at over 270 recorded bird species.

Because the arboretum runs along Queen Creek in a riparian zone, it pulls in migrating birds alongside the resident desert wildlife.

You might spot a bobcat, a javelina, a coatimundi or a Gila monster between the garden beds. Down at Ayer Lake, endangered desert pupfish were restocked in 2025 as part of ongoing native fish recovery work.

Guided bird walks run seasonally, and you can borrow binoculars at the admissions window.

A wheelchair-friendly loop and a trail for desert medicine

The 1.5-mile main trail loop leaves from the visitor center and takes you past most of the major exhibits and gardens. Most of it works for wheelchairs and strollers.

If you want elevation, the High Trail climbs 0.45 miles through the Upper Sonoran natural area with wide-open desert views. The Curandero Trail is different.

It focuses on medicinal and edible plants that native peoples of the Sonoran Desert have used for generations. Side paths branch off into the Chihuahuan Trail and the Wallace Desert Garden.

South American sculptures and herbs around a stone house

The cactus and succulents garden holds common, rare and endangered species from across North and South America.

Nearby, the Chihuahuan, Sonoran and Mojave desert exhibits line up side by side so you can see how plants adapted differently in each region.

Over in the South American exhibit, landscape sculptures by Zimbabwean artist Euwit Nyanhongo sit among the plantings.

Then there is the Wing Memorial Herb Garden, wrapped around the historic Clevenger House, where culinary, medicinal and cosmetic herbs grow in neat rows.

A suspension bridge and a mansion built like a Greek monastery

Cross the suspension bridge over Queen Creek, and you can look up at the Picket Post House perched on the cliffs.

William Boyce Thompson built that 1920s winter mansion to resemble a Greek cliffside monastery, and while it is not regularly open for tours, you can see it from the trails.

Below the cliffs, the Clevenger House sits in a shallow cave in the mountainside, a stone homestead from the early 1900s that Thompson’s grandchildren later used as a playhouse.

Ayer Lake nearby gives you a bench and a quiet place to sit.

A kids’ maze and stargazing after dark

The Children’s Garden has a maze, a mosaic walkway and hands-on activities that keep younger visitors busy.

Beyond that, the arboretum runs guided tours and specialty walks on birds, geology and ethnobotany, plus a Branching Out lecture series. When the seasons shift, so do the programs.

You can catch stargazing evenings, sunrise hikes, yoga in the garden and family events throughout the year. Near the entrance, you will find a visitor center, gift shop, greenhouses, a picnic area and a plant nursery.

100 native trees planted for a 100th birthday

The arboretum hit its centennial in 2024 and marked it with a 100 Tree Spree, planting 100 native trees at schools and nonprofits around the area.

A century in, the place still follows the same path William Boyce Thompson set in the 1920s. Research, conservation and public access run side by side here, just as he planned.

You walk the same grounds where botanists first cataloged new species, and the mission to protect desert plants and ecosystems has only grown deeper with time.

Visit Boyce Thompson Arboretum in Arizona

You can find Boyce Thompson Arboretum at 37615 E. Arboretum Way in Superior, Ariz., right along U.S. Highway 60. Hours shift with the seasons.

From October through March, the gates open daily from 8 a.m. to 5 p.m. Summer months start earlier, sometimes as early as 6 a.m., with shorter days and Tuesday closures from June through August. Dogs on leashes are welcome on the trails.

Check the official website before you go, because the schedule changes often.

This article was created with AI assistance and human editing.

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