Group of people standing on paved desert park path beneath tall palm trees — From fallen oak to future desert bed — volunteers prep the area for our newest arrivals.

Expanding our Desert Collection

Visiting Tucson-area gardens and nurseries to find new plants

by Kitty Bolte, horticulturist
Wed, August 19, 2026

Smiling woman in sun hat holding a long receipt under a pavilion with blue sky — Kitty Bolte (me!), horticulturist, with a long receipt showing multiple desert collection purchases.

In 2025, we were approached by the San Francisco Succulent and Cactus Society about applying for a grant. The timing was excellent as a large heritage oak tree had recently come down in our Desert collection. Although we were sad about the tree, it did mean our sunny real estate for desert plants was significantly expanded. We applied and were awarded funding from SFSCS to travel to Tucson, Arizona to visit nurseries and botanic gardens with the purpose of learning about best practices for desert horticulture and bringing back plants to add to our collection.

In March of 2026, two of our staff members flew to Tucson and picked up a rental box truck. We visited four local native plant nurseries (Spadefoot Nursery, Nighthawk Natives Nursery, Civano Growers - Wholesale Plant Nursery, and Borderlands Restoration Network / Borderlands Nursery & Seed) as well as the incredible Arizona-Sonora Desert Museum. Staff at all of these locations were very generous in sharing their time and expertise, not to mention plants! In the end, we drove home with a truck packed to the gills with nearly 300 specimens representing 115 taxa. Since then, we’ve been hard at work planting them in Arboretum collections.

It is difficult to pick highlights from such a great group of plants, but a few we are especially excited to be adding to the collection include ocotillo (Fouquieria splendens); the iconic saguaro (Carnegiea gigantea); Palmer’s agave (Agave palmeri), an agave with great ethnobotanical significance to Indigenous societies in the Southwest; and desert ironwood (Olneya tesota), a beautiful tree characteristic of the western Sonoran Desert.

Emily Griswold, director of GATEways horticulture, discusses appropriate plants for potential inclusion in our Desert Collection.

We also received some unusual large shrubs and small trees, including formosa lippia (Lippia formosa), Wright’s silktassel (Garrya wrightii), Hind’s nightshade (Solanum hindisanum), dwarf bird-of-paradise (Caesalpinia pumila), and mauto (Lysiloma divaricatum), as well as some interesting vines, including fringed twinevine (Funastrum cynanchoides), a member of the milkweed family; Watson’s Dutchman’s pipe (Aristolochia watsonii); and purple bush-bean (Macroptilium atropurpureum).

While we are continuing to grow some specimens to larger sizes prior to transplanting, many are already planted in Arboretum collections and can be viewed by visitors. Most specimens are in our Desert Collection, located on the north side of the Arboretum Waterway approximately halfway between Mrak Hall Drive and La Rue Road.

The UC Davis Arboretum is free and open to the public at all times, although visitors do need to pay to park on campus during the work week. Parking is free on the weekends except during special events.