What it is
Boyce Thompson Arboretum is the oldest botanical garden in Arizona and the largest: 392 acres along Queen Creek where it cuts a canyon below Picket Post Mountain, a volcanic remnant three miles west of the copper town of Superior. William Boyce Thompson, who made his fortune in copper and spent some of it on plants, founded it in 1924 as a research garden for the arid regions of the world, and it was the state’s first nonprofit research institution before it was anybody’s day out. Today it holds more than 2,600 species, from the Sonoran Desert’s own saguaros and ironwoods to boojums from Baja, cardóns, Australian eucalyptus, South African aloes and a grove of pistache that turns red in November.
The main trail is a 1.5-mile loop along the creek and up through the canyon, past Ayer Lake, built in 1926 to water the lower garden, the Smith Building’s old greenhouses, the cactus and succulent gardens and a stretch of riparian shade that feels like another state. Across a bridge over the creek is the newest and, for this site, the most interesting part: the Wallace Desert Garden, 13 acres with 1.5 miles of its own trails, assembled from nearly six thousand plants dug out of a private garden in North Scottsdale and trucked seventy-five miles here beginning in December 2015.
Why leave Scottsdale for it
Because the Desert Botanical Garden is the explanation and this is the field trip. Boyce Thompson is older, bigger, wilder and about a third of the price, with a real creek and a mountain, and the crowds are a fraction. It is also the one botanical garden in the Valley that lets you bring the dog. And a piece of Scottsdale is in it.
The practical version
About 75 minutes from Old Town on US 60, the farthest drive in this section. Daily in the cool months from about eight to five, last entry an hour before closing; summer is early mornings only and Tuesdays are closed from June through August. Two hours for the main loop, half a day with the Wallace garden and a picnic. Go in spring.
When to go
Late February through April is the reason the arboretum exists in a visitor’s calendar: wildflowers along Queen Creek, the cactus garden in bloom through April, and temperatures that let you walk the whole property. Weekends in March are busy by the arboretum’s standards, which means a full main lot and not much else.
November is the other season, and the one nobody expects. The pistache grove and the cottonwoods along the creek turn, and for two or three weeks the canyon has something like autumn. Our plants field guide covers what blooms when in the low desert; this garden adds a hundred species it does not.
Summer is for the early-morning schedule only, with the gates opening at six and last entry before noon, and the garden closes on Tuesdays from June through August. The creek stretch is pleasant until about nine; after that it is a desert.
The walk, in order
- The main loop, clockwise. Up the canyon side first while it is shaded, then back along the creek and the lake.
- The Wallace Desert Garden. Over the bridge; the boojums, the big cardóns and the agaves that made H.B. Wallace’s collection famous among people who care about such things. The 1.5 miles of trail are gentler than the main loop.
- The cactus and succulent gardens and the Smith Building. The old greenhouse complex, now a shady place to end.
- Lunch by Ayer Lake. Bring it; the picnic tables are the best in the East Valley.
With kids and dogs
The creek is the kids’ part: shade, water in winter, lizards, and the lake with its turtles and ducks. The main loop has grades but no drop-offs that worry a parent. Dogs go everywhere on a six-foot leash, and our Scottsdale with dogs note lists this as the one botanical garden where that is true.
The story
William Boyce Thompson was a Montana-born mining financier who built a fortune in copper, founded a plant research institute in New York, and wintered at a house he built on Picket Post Mountain above Queen Creek. In 1924 he established the arboretum below it as a research station for the plants of the world’s deserts, with the idea that arid-land species collected from every continent could be studied, grown and compared in one Arizona canyon. By 1926 the Smith Building and its greenhouses were up and Ayer Lake had been dug to irrigate the lower garden. The arboretum stayed a scientific institution first and a public garden second for decades, and in 1965 a cooperative agreement made it the University of Arizona’s Desert Biology Station. A three-way agreement signed on March 30, 1976, brought it into the Arizona State Parks system while it kept its nonprofit research identity, and Arizona State Parks later bought Thompson’s Picket Post House above it.
The Wallace Desert Garden is the chapter that matters to a Scottsdale reader. Henry B. Wallace, of the Wallace family whose fortune came from hybrid seed corn, spent decades building one of the finest private collections of arid-land plants in the country on his property in North Scottsdale: boojums, cardóns, agaves and aloes from around the world. When he died in 2005 his foundation could not maintain the garden and did not want it broken up. In 2014 the arboretum agreed to take the whole thing, and beginning in December 2015 the staff dug up 5,870 plants, some of them decades old and tons in weight, and moved them seventy-five miles by truck, car and semi to a new 13-acre site across Queen Creek, with a bridge built to reach it. It is now open, with 1.5 miles of trail and more than five thousand plantings, and it is the largest transplanted desert garden anyone knows of.
The Scottsdale connection
Scottsdale lost a world-class garden it never knew it had; the Wallace collection was private and most locals never saw it. It is here now, labeled and walkable. The city’s own public version of the idea is the small Xeriscape Garden at Chaparral Park, which teaches the same lesson in a tenth of the space: what grows here, and what to plant instead of lawn.
Getting there
From Old Town, the 101 south to the 202 east, the 202 to US 60 east, and stay on US 60 through Mesa, Apache Junction and Gold Canyon, about twenty-five miles of two-lane highway into the hills past the Peralta Road and Queen Valley turnoffs; the arboretum entrance is on the right three miles before Superior. About 75 minutes from Old Town with no traffic. Superior itself has a few restaurants on its old main street for lunch afterward, and the drive back past the Superstitions at sunset is the better direction. Our day trips note has the long version of the day.