Official Symbols of the State of Arizona State flower: Saguaro cactus blossom In mid-April, the cream-colored flower of the saguaro, Cereus giganteus, begins to bloom. The flower opens after sunset and closes by noon of the following day, never to open again. Moths, bats, birds, and insects must pollinate each flower in less than 24 hours. Each flower will produce about 2,000 seeds. State tree: Palo Verde Several species of Palo Verde trees are found in the Arizona desert. The trees are usually from 12 to 20 feet high. They have green to blue-green bark with leafless branches for much of the year. However, when the winter rains come, an explosion of tiny leaves appear. From mid-March through May brilliant yellow flowers cover the trees. Palo verde trees are usually found along the banks of desert washes. Saguaro cactus blossoms Palo Verde tree 170  Chapter 16 • Arizona in the 21st Century