It contains plants from extreme environments, many of which were acquired by Henry E. Huntington and William Hertrich (the garden's first curator) in trips taken to several countries in North, Central and South America.

[1] Huntington was not initially interested in establishing a Desert Garden because he did not like cacti at all, owing to some unfortunate prickly pear encounters during railroad construction work.

But Hertrich was persistent, and, once won over, Huntington built a railway spur to his garden in order to bring in rock, soil and plants by the carload.

As Gary Lyons, a later curator, remarked, "...it's very convenient to have a rail spur, and deep pockets, when you're building a big garden".

They form the structure of much of the Desert Garden landscape, producing flowers in late summer and colorful fruit in September and October.

The columnar cactus-like plants in the African section of the Desert Garden are succulent spurges (Euphorbia) and have caustic milky latex.

Crown of Thorns (Euphorbia milii), the familiar house plant, is a spiny native of Madagascar that produces colorful bracts throughout the year.

The garden has the largest collection of living stones in America, small southern African plants of the genus Lithops.