The bird of paradise is one of the most popular non-native well-adapted shrubs that are suitable for the low desert of Arizona. There are three species in the family Fabaceae and genus Caesalpinia (formerly called Poinciana) that often go by the common name of bird of paradise and each of them have additional descriptive modifiers on the common name: yellow, Mexican, and red. While they all have similarities, they also have differences and understanding them allows the gardener to make an informed decision about putting the right plant in the right place. None of these three plants should be confused with the bird of paradise plant grown commonly in southern California and Florida gardens, which is in a different botanical group (Strelitzia genus) and is not easily grown in desert gardens because it requires a cool moist climate. In addition, there are three more shrubs in the Caesalpinia genus that could be considered in a low desert situation. They are cascalote (Caesalpinia cacalaco), palo Colorado (Caesalpinia platyloba), and copper Caesalpinia (Caesalpinia pumila).
This resources compares differences between the three bird of paradise species and is followed with general information applicable to all three species.