Saving a priceless collection – of plants

Boyce Thompson Arboretum to the Rescue: The effort to save the Wallace Desert Gardens

Boyce Thompson Arboretum recently announced that it is part of a massive effort to save the plant collection of Wallace Desert Gardens. Located in north Scottsdale, this garden contains 12 acres of more than 7,000 cultivated plants, including a 6,000 square foot pavilion of large specimen cacti.

HB Wallace built the Wallace Desert Gardens over 25 years ago and amassed 3,000 species of plants, including a wide variety of ephedras, boojum trees, agaves, cacti, and aloes. Adding this plant collection to the one at Boyce Thompson Arboretum will create a superlative garden of plants from arid lands around the world.  With over 4,300 species combined, Botanic Gardens Conservation International estimates this plant diversity will place Boyce Thompson Arboretum in the top 100 gardens globally, and top 25 in the United States.  

Mark Siegwarth, Executive Director of Boyce Thompson Arboretum, says, “This unprecedented project to relocate 7,000 plants in the Wallace Collection to Superior will be complicated, but we know this project is extremely important as over one fourth of the combined collection is held in fewer than 10 gardens globally, with a significant number representing threatened species.” 

“Expanding the garden area at Boyce Thompson Arboretum will allow us to create an even larger trail system with more educational and recreational opportunities to better fulfill our mission as an Arizona State Park,” continues Siegwarth.  “The sheer biological diversity of the combined collections will permit us to expand our mission of research and conservation in our other role as a University of Arizona Experiment Station.”

Lee Brownson, Executive Director of the Wallace Desert Gardens, is extremely pleased the entire collection is to be relocated to Boyce Thompson Arboretum.   “H.B. Wallace, and indeed several generations of the Wallace family, have been instrumental in agricultural research over the years.  Both garden founders were committed to finding ways plants could benefit mankind.  It seems fitting that although the gardens were started in different locations at different times, together they can further the founders’ original intents.”  The Wallace Desert Gardens has had a long relationship with both Boyce Thompson Arboretum and its Desert Legume Program at the University of Arizona.

With the Wallace Desert Gardens Board of Directors’ desire to share this collection with the public and continue their founders’ interest in agricultural research, Boyce Thompson Arboretum seems a natural fit with its dual role as a University of Arizona Experiment Station and as a State Park. Wallace Desert Gardens Acting Board President Joe Giacobazzi says, “The move to Boyce Thompson Arboretum is really the perfect solution and fit for the Wallace Collection.”

Although this is a novel way to rescue a garden, it will not happen overnight. It will take approximately three years to move the plants and perhaps five years to integrate both operations. Each plant will have to be individually evaluated to determine the best method and time of year to be moved. “We have so many microclimates,” Executive Director Seigwarth says, “we want to find the perfect place for each plant.”   

The Arboretum will be constructing a new loop trail for the Wallace collection, so there should be minimal impact on visitors. A few plant specimens may be relocated to existing areas at the Arboretum in order to more fully develop those exhibits.

Visit the Arboretum’s Facebook page and website for the latest information as plans become more solidified in anticipation of the start of relocating the Wallace  Desert Gardens plant collection to Boyce Thompson Arboretum.