Psorothamnus fremontii, the Frémont's dalea or Frémont's indigo bush - after John C. Frémont, is a perennial legume shrub. Psorothamnus fremontii is common to the Southwestern United States and Northwest Mexico - in the states of California, Nevada, Utah, and Arizona, Sonora, and Baja California. Psorothamnus fremontii is common to the Southwestern United States and Northwest Mexico - in the states of California, Nevada, Utah, and Arizona, Sonora, and Baja California. The plant is found in the Sonoran Deserts, including the Colorado Desert, the Great Basin Deserts, and in the Mojave Desert sky islands, from 250-1,350 metres (820-4,430 ft) in elevation.