This courtyard-style garden pays homage to the desert-dwelling members of the world’s third largest plant family, the legumes.
Members of Fabaceae, the legume family, range in size from small annual vines to large trees, and include many common desert trees. The first legumes were planted in the garden in 1989, with funding provided by the family of Keith Taylor Sr. and several of Arizona’s green industries. Today, 121 different species are housed in the garden, represented by around 328 individual plants.
Why Legumes?
Legumes have been an important food source for humanity since the dawn of mankind. Economically, legumes constitute the world’s most important food crops, second only to grains. Seeds are high in protein, pods are often sweet yet have a low glycemic index, and the sprouts and leaves of many species are edible. The pods of our native velvet mesquite (Prosopis velutina) have been used to make flour for centuries and the carob (Ceratonia siliqua) has been cultivated for its sweet pods just as long in the Middle East. In industry, legumes provide dyes and tannins, gums to thicken foods, and quality wood for flooring, tools, artwork, and timber. Many species, such as the globally cultivated alfalfa (Medicago sativa), provide forage for the cattle and other livestock that feed the world.
With their diverse array of flowers, legumes also provide us with beauty. Here in the desert, many of our common ornamental plants, such as the orange- and-yellow flowered Mexican bird-of-paradise (Caesalpinia pulcherrima), the fragrant purple Texas mountain laurel (Dermatophyllum secundiflorum), and the hummingbird-attracting red Baja fairy duster (Calliandra californica) are none other than desert legumes.
The Desert Legume Program
The garden was conceived by the Desert Legume Program (DELEP), a joint project between the University of Arizona and Boyce Thompson Arboretum, whose mission is to both conserve desert legume biodiversity and to educate the public on the many uses of these important plants.
Most legumes possess the ability to convert atmospheric nitrogen to a usable form through an elaborate association with bacteria in their roots. This capability has allowed drought-adapted legumes to thrive in arid regions, such as the world’s deserts, where soil nitrogen is scarce. In harsh, nutrient-poor environments where most plants fail, legumes succeed. Most of our Sonoran Desert’s iconic trees, such as the mesquites, palo verdes, and ironwood, are, in fact, legumes.
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Catch the Yarrow blooms in the Demonstration Garden and the Herb Garden.
New here? Let us show you around.
Welcome to Boyce Thompson Arboretum—Arizona’s oldest and largest botanical garden.
Explore winding trails, desert blooms, and 343 acres of living beauty just outside Phoenix.
Come curious. Leave inspired.
Calling all teachers! Boyce Thompson Arboretum invites you to join us for our professional development sessions. Come spend time with us as we familiarize ourselves with the 5E Instructional Model and explore desert plant adaptations! Pre-registration is required. Space is limited. Visit https://btarboretum.org/pd/to apply.
✨Summer Golf Cart Tours ✨
Explore the arboretum this summer with our staff on a golf cart tour! We invite you to join us for an hour long cart ride to some of our most scenic spots of the arboretum. Our knowledgeable staff will give you insights into our collections and take you to the best photo ops the gardens have to offer.
Wednesdays-Saturdays in June, July, August between 7:00am-8:00am, 9:00am-10:00am, 11:00am-12:00pm
Cost: $20 per person, plus the cost of admission.
Cart tours are first come first served with a limit of 5 guests. Ask about availability at our Visitor’s Center Wednesday through Saturdays this summer!
Some exclusions apply
Make the most of your mornings this summer! From June through August, Boyce Thompson Arboretum is open Wednesday through Monday, 6:00 a.m. to 12:00 p.m., with last admission at 11:00 a.m. We are closed on Tuesdays.
Plus during these months enjoy special admission rates:
Ages 13 and up – $16
Children 5–12 – $10
Children under 5 – Free
Visit early, explore the trails, and soak in the beauty of the Arboretum in the cooler part of the day.
Tiny cuttings, big impact.
Every plant you see here started from just a snip — carefully cleaned, dipped, and rooted with care. Propagation isn’t just practical. It’s powerful. It helps us grow more plants for pollinators, restoration, and education — all while conserving precious resources.
But we can’t do it alone. Your support helps us expand our propagation efforts and grow the future of this garden.
Think you`re seeing bark? Look again. You might be spotting the Ornate Tree Lizard. But once you see it...you can`t unsee it.
If you grew up in the Southwest, this flower might be part of your childhood. The Desert Willow is back in bloom in the garden and just as magical as you remember.