Speaking of fast-growing shade trees that can tolerate extreme conditions: The palo verde (Parkinsonia florida) is a desert native that produces an incredible show every spring via a burst of tiny yellow blooms. These flowers are so dense that they provide nice shade. When not blooming, the lush green leaves step in to provide respite from the desert sun. In the winter, when temperatures are cooler and days are shorter, it drops its leaves and becomes bare.