The Night-blooming Cereus cactus (Peniocereus greggii) is now hiding among desert shrubs which provide shade and physical support, but it will soon make itself known some time during late May to early July. The cactus stems are thin, barely succulent and often few in number. The stems rarely get over three feet high. They grow from a root, a large, starchy tuber, that can weigh over 40 pounds. If stems are eaten by desert critters such as packrats, new stems sprout from the root. Some synonyms for its name are Arizona queen-of-the-night, sweet-potato cactus, and deer horn cactus.
Although the cactus itself is inconspicuous, the flower is spectacular. The flower is bright white and up to three inches in diameter with very long floral tubes and a strong, sweet scent that attracts sphingid moths which are the main pollinators. Some people say the scent is like vanilla. The flowers close up soon after sunrise.
The Night-blooming Cereus ranges from Southern Arizona to southern Texas and adjacent northern Mexico, as well as in Baja California.
According to the Arizona-Sonora Desert Museum:
“This is one of the Sonoran Desert’s most famous yet least encountered plants. It is virtually invisible most of the year, but on a few nights it becomes stunningly conspicuous. Plants in each population bloom in synchrony; large ones can produce a score of flowers at once. The legend is that they all bloom on a single night per year. Reality is almost as intriguing: each plant produces only three to five flushes of flowers between late May and early July. During each flush most of the flowers open on one night, with a few stragglers the night before or after the big bang.”
ASDM goes on to note:
“In ideal cultivated situations where the plants are protected from predators, these cacti can grow hundreds of times larger than they do in nature. Archaeologist Julian Hayden had a plant in his Tucson yard that was over 8 feet tall and perhaps twice as wide. Its great tangle of stems produced 200 flowers on one night and another 100 on the following night.”
“Desert night-blooming cereus plants usually occur as widely-separated individuals, and the flowers are not self-fertile. The flowers are cross-pollinated by hawk moths (Sphingidae) which fly hundreds of yards between plants in their search for the nectar reward. The cactus fruit turns red when ripe, attracting birds that eat the pulp and disperse the seeds in their droppings. The root is used medicinally to treat diabetes and other maladies.”
According to the US. Forest Service, this cactus “is called ‘pain in the heart’ by the Death Valley Shoshones. This tribe presumably uses it in a manner similar to Native Americans of Nevada who ingest an infusion of the roots as a cardiac stimulant. Other Native Americans have used a decoction of the roots for diabetes, the seedpods mixed with deer fat as a salve for sores, and the cut slices of root as an externally applied cure for chest colds. The fruits, flowers, young stalks, and roots have been eaten for food. This use of the root may account for the common name ‘sweet potato cactus.’ Chewing the raw root has been reported to quench thirst.”
See more photos at ASDM digital library here.
Tohono Chul botanical garden in Tucson has a large collection of Cereus and hosts a “bloom night” every year.
For information on other desert plants see: