The magnificent Saguaro Cactus is the state flower of Arizona. It is composed of a tall, thick, fluted stem column that grows from 18 to 24 inches in diameter, with several large branches, which the locals refer to as arms, curving upward in a distinctive formation frequently likened to natural sentries. its skin is smooth and waxy, while the trunk and stems have stout, 2-inch spines clustered at their ribs. When water is absorbed, the outer pulp of the Saguaro expands like an accordion, which increases both the diameter of the trunk and stems and its weight up to as much as a ton.
During the critical germination stage, surviving Saguaros usually have found the shelter of a “nurse” tree or shrub which assures shade and moisture. Although it only grows about an inch a year in its early life, it can reach a height of 15 to 50 feet at maturity. The largest plants have five or more arms and are estimated to be about 200 years old. An average age Saguaro has about five or more arms and stands 30 feet high.
Its flowers are creamy white with yellow centers that open to about 3 inches in diameter. As the following description by Dad reveals, (from his photographic book Barry Goldwater and the Southwest,) the blossoms only open during the cooler desert nights and close again by the next midday:
"The desert corsage, a picture of two blossoming flowers of the giant saguaro taken about 1936. These flowers bloom at night and start dying as soon as the sun rises."
- Barry M. Goldwater