One of the most interesting (and exotic) small trees that do well in a desert garden is the chokecherry (prunus virginiana).
Growing 12 to 25 feet (in the desert, expect 12 feet rather than 25), this plant makes an attractive addition. The fruits, although edible, have a very tart, almost astringent taste, and are better used to make jellies and wine than to eat raw. The pits, as are many pits in the prunus family, are poisonous to humans, pets and livestock.
However, birds love the fruit, and many species will be attracted to your garden in search of them.
The leaves are very attractive, as is the bark. The leaves are dark green above, and lighter green below. In the fall, they turn a very attractive and bright yellow. The bark is a dark reddish brown, adding an extra attraction to both the green leaves in spring and summer, the yellow leaves in the fall, and a very nice color against snow in winter.
The creamy-white blooms are three-to-six inch long racemes and produce a pungent odor. The fruit is dark red to purple-black when mature.
In addition to eating the berries and using them to season and flavor, Native Americans used the leaves as an emetic for stomachache and nausea. The Navajo us the leaves and stems, with pounded juniper branches for a yellow-brown dye.
Both Hopi and Navajo ingest the leaves (which are very bitter) to induce vomiting. They also use a leaf broth to wash wounds and treat skin problems.
Chokecherries are extremely adaptable to many soil types. I have several growing in my desert garden, two in very alkaline soil, which are all thriving.