Saguaro blossom, the state flower of Arizona

A flower that lasts a day

Saguaro blossoms are large and creamy white, with a thick cluster of yellow stamens at the center. They grow in crowns at the tips of the saguaro’s trunk and arms, and sometimes along its sides. Each flower opens after dark and closes the following afternoon, so it has less than a day to be pollinated.

That short window is filled by a night and day shift of visitors. At night nectar-feeding bats push their faces into the flowers. In the morning white-winged doves, hummingbirds, bees and other insects take over. A single saguaro opens a few flowers at a time over several weeks, which spreads its chances.

The bloom runs from late April to early June. Pollinated flowers become red, juicy fruits, each holding about 2,000 tiny black seeds. Birds, bats and other animals eat the fruit, and the Tohono O’odham people harvest it each summer.

The giant behind the flower

The saguaro is the largest cactus in the United States. It commonly grows 40 feet tall and can reach about 50, with a pleated, spiny trunk that swells to store water after rain. It grows slowly: a saguaro usually flowers for the first time at about 35 years old and may not grow its first arms until it is 50 to 100.

It grows only in the Sonoran Desert, mainly from central Arizona south into Sonora, Mexico, generally below about 4,500 feet, because it cannot survive hard freezes. Young saguaros often begin life in the shade of a “nurse” tree, frequently a palo verde, Arizona’s state tree.

Where to see the bloom

Saguaro National Park, on both sides of Tucson, protects one of the largest saguaro forests. Peak bloom there usually comes in the last week of May and the first week of June. Look up: the flowers are often at the very tops of the cactus, 30 feet or more above the ground. Early morning, before the flowers start to close, is the best time.

Protected by law

Saguaros are protected under Arizona’s native plant law. Moving or salvaging a saguaro from where it grows requires a permit, tag and seal from the Arizona Department of Agriculture, although cactus grown by people are exempt. For the Tohono O’odham the saguaro is a sacred plant, used in ceremony and for food.

The state flower since 1931

The saguaro blossom was chosen as Arizona’s territorial flower in 1901 and confirmed as the state flower in 1931. The law, now section 41-855 of the Arizona Revised Statutes, describes it as “the pure white waxy flower” of the giant cactus, which it calls by an older name, Cereus giganteus.