Parkinsonia praecox, the Sonoran Palo Verde, is also called the Palo Brea. The Palo Brea is a lovely sculptural palo verde species, with smooth lime green bark and semi-evergreen blue-green leaves. The Palo Brea is hardy only in the warmer parts of the Tucson area, and is not a suitable plant for Green Valley. The Palo Brea is a native plant to Mexico.
The Palo Brea is a great specimen tree because of its sculptural form. Planted with other desert plants, it compliments the olive to gray-greens of many desert species. The spring yellow flowers a color to your yard, but attract bees, so keep that in mind if you are allergic.
Plant palo verde species where drainage is good, and always provide supplemental irrigation. They prefer full sun for best flowers and performance. Although drought tolerant, these need irrigation to look their best.
Reference: Mountain States Wholesale Nursery and Gregg Starr Nursery Plant Info Sheet, 1999.