Boyce Thompson Arboretum – AZ’s Largest and Oldest Botanical Garden!

In March 2015, with the pomp and fanfare of a heavily-loaded semi crossing the threshold of the front gate, the Wallace collection plants first arrived at Boyce Thompson Arboretum.  

It all started in 2014, when the Wallace Desert Gardens Foundation approached Boyce Thompson Arboretum with an audacious request—to save Henry B. Wallace’s collection of desert plants. HB, as he was known, had passed away in 2005 and his foundation was no longer able to maintain the valuable collection. Saving it meant agreeing to the transport, acclimation, and transplanting of some 6,000 plants, and included designing an entirely new garden at Boyce Thompson Arboretum. BTA said yes. 

The Wallace collection of desert plants was originally located inside the Scottsdale-based Sincuidados private home development. To move the collection, it took teams of landscapers hand digging trenches around the bases of the plants. For a 25-foot cactus, wooden panels measuring 72" were used to build boxes in the holes around the base. Even the large yucca and saguaros had to be prepared using this method before they could be moved to BTA. A front-end loader was used to load the boxed plants and it took 100 semi-truck loads to get them to BTA. 

The plants were transferred to six shade houses and the staff watered them regularly and checked them for shock. Jeff Payne, a certified arborist, oversaw the replanting of 2,200 boxes of plants. 

This project is groundbreaking not just because of its scale, but because of the quality and diversity of the Wallace Desert Gardens collection. Of the 1,439 taxa (species, cultivars, hybrids, varieties) transported to Boyce Thompson Arboretum, 861 are new to BTA, and 159 species or 14.4 percent are considered to be of conservation concern, ranging from vulnerable to critically endangered in the wild.

Adding them to the Boyce Thompson Arboretum creates an unprecedented collection of desert plants from the United States, Mexico, Australia, Madagascar, India, China, Japan, Israel, South America, the Middle East, Africa, the Mediterranean, and the Arabian Peninsula. 

Today the garden is thriving in its new location and the combined collections rank BTA as the first in the world in the number of desert legume taxa.