Psorothamnus arborescens is a species of flowering plant in the legume family known by the common name Mojave indigo bush.

Psorothamnus arborescens is native to southwestern North America, where it can be found in many types of desert and dry mountainous habitats.

Psorothamnus arborescens is a shrub growing no more than 1 metre (3.3 ft) tall, its highly branching stems sometimes with thorns.

The leaves are each made up of a few pairs of green linear to oval leaflets up to a centimeter in length.

[3] The varieties of this species are generally similar in appearance but more restricted in distribution: