In the southwest corner of the Arboretum, there is an interesting collection known as the Southwestern Garden, where plants from Mexico and the American Southwest thrive. Here, plants remind one of a dry North American near-desert, including some referred to by the curiously contradictory name "woody lilies." Several species and types of Yucca, Agave, Nolina (beargrass), Dasylirion (sotol or desert spoon), and Hesperaloe (red yucca) predominate. Cacti also grow here, including Opuntia (prickly pear) and Echinocactus.
Over the years, the nearby trees here have grown, creating more shade than is ideal for their sun-loving neighbors. Southwestern plants often prosper in a site that has plenty of sunshine, heat, and good drainage. Renovation began in and around the Southwestern Garden in 2006. The newly renovated and expanded garden became the Xeric Garden.