Parkinsonia microphylla, also known as Yellow Palo Verde or Foothills Palo Verde, is a native tree with smooth green bark up that grows to 20ft. Flowers are bicolored with four yellow petals and one white banner. A dominant on the dry rocky hillsides of the Sonoran Desert. Abundant on bajadas, plains and hillslopes through low desert from 500-3,500 ft (152-1067 m).  Grows across w AZ, se CA, Sonora and Baja California, Mexico. Flowers April-May. Plant in full sun with low to medium irrigation and well-draining soil. No shipping.