The Senita Cactus

Lophocoreus schottii

by Joe Zentner


Nature dug two incredibly big holes – the Grand Canyon and Canyon de Chelly – in Northern Arizona, fortunately for those of us who love the solitude and quietness of the phantasmagoric cactus country farther south, near the border between Arizona and Mexico’s Sonora.

While folks from Hackensack, Burbank, Topeka (my hometown) and Amsterdam wander around or through the big holes, my wife and I head south, down into the Sonoran Desert to listen to the wind, smell the creosotebush, skirt the various cholla cacti, and watch red-tailed hawks circling in the sky high above us.  We feel the desert.  We revel in botanical masterpieces, the cacti of the Sonoran Desert.  (We also make certain that we’ve got plenty of water.)

Organ Pipe Cactus National Monument

Meanwhile, we’re getting to be on a first-name basis with some of the desert cacti.  In Organ Pipe Cactus National Monument, located on the border with Mexico, the star of the botanical stage is, obviously, the organ pipe cactus.  It also has a lesser known, but also spectacular relative, the senita cactus, one of our favorites. 

Senita or old man cactus blooms from April to August.


The 330,000-acre monument has more to offer than organ pipe and senita cacti.  It has well over 500 species of plants, 50 species of mammals and 40 kinds of reptiles.  You may find, for a few examples, gila monsters, western diamondback rattlesnakes, an occasional desert tortoise, various quail, roadrunners, coyotes and javelinas. 

Organ Pipe Cactus National Monument, well isolated from today’s busy metropolitan areas, was originally the domain of Native Americans, then the Spanish Crown and, after 1821, the Republic of Mexico.  The land came to the U. S. as part of the Gadsden Purchase in 1853, when we paid Mexico $10,000,000 for the southwestern corner of New Mexico and the southern part of Arizona, making way for a railroad.  

The monument encompasses three different parts of the Sonoran Desert.  The easternmost part is called the Upland Arizona Succulent Desert, which is one of the most botanically diverse arid regions in the world.  It supports, for instance, stands of saguaro, teddybear cholla, numerous prickly pears and several agaves.  The westernmost part – lower, hotter and drier – is called the California Microphyll Desert, where you will find the highly desert-adapted creosotebush and sage.  The third part, a finger extending up from Mexico’s Gulf of California into the monument, is called the Central Gulf Coast Phase, and it is here that you will find the organ pipe and senita cacti as well as the bizarre elephant tree, a plant found nowhere else in the United States.

The Monument and the SenitaNeedles block up to 80 percent of the sun's rays at their tips.

When visiting the National Monument, take Ajo Mountain Drive first.  Numbered stakes along the way, coupled with a guide booklet, will familiarize you with many desert plants and other natural phenomena.  Don’t be fooled by the seemingly short 18-mile-long length of this one-way loop road.  You can make a whole day of it, with many rewarding stops.  (Be certain to take plenty of water.)

Although the monument is named for the Organ Pipe Cactus, we find the senita cactus to be particularly interesting.  You will find stands of them at Senita Pass, reached by a side road leading north.  The senita grows here and in Mexico’s Sonora and Baja California.  The senita (Lophocoreus schottii) prefers silty flats and rocky hillsides.  Its genus name Lophocereus means “crested cactus.” The species name schotti honors Arthur Schott (1814 to 1875), who worked with the Mexico Boundary Commission as a plant collector.  The senita, one of the columnar cacti, has many stems up to eight inches wide and 15 feet high, branching up from the base.  Each stem has five to 10 ribs.  The upper sections of adult stems produce spine clusters (areolas), each with 15 to 20 bristle-like gray spines one to four inches long.  Its flowers, pale pink, are produced mostly from the upper stems.  The flowers open after dark and close around dawn.  They are pollinated by a small moth specialized to live its life on this cactus.  The senita fruits are spineless, red and fleshy when mature.

Senita Fruit

Human Uses

The Seri Indians and others ate the tasty senita fruits fresh.  The Seri used the spiny cactus wood to build shelters.  Early Native Americans believed the senita to have a powerful spirit, given by Icor, the spirit of vegetation.  The senita spirit, at one time, was consulted for placing curses that were thought to lead to sickness and death of an enemy.

At the Senita Basin in Organ Pipe Cactus National Monument in the late afternoon, you can lean against a slab of pink granite in the lengthening shadow of a gray-bearded cactus, and you can think about Icor, or you do nothing at all while the sun subsides, the twilight falls, the planet spins, and the fading light transforms brown to orange and rust to red.  In the stillness, you can contemplate life’s meaning, if there is any (with apologies to Jean-Paul Sartre).

Senita cactus flower

Getting There 

From Phoenix, you can follow State Highway 85 south for about 120 miles to reach the monument.  From Tucson, you would follow State Highway 86 west for about 120 miles to the intersection with SH 85, then turn south into the monument.  From Yuma, you would follow Interstate Highway 8 eastward for about 120 miles, to Gila Bend, then turn south on SH 85, following it for some 55 miles to the monument.  From Yuma, you can save some mileage if you drive south on U. S. Highway 95, cross the border at San Luis, then follow Mexican Highway 2 east for about 130 miles to Sonoita, where you would turn north across the border and into the monument.  You will not need tourist cards as long as you stay on the road, within a few miles of the border, but you should have a title or a lien-holder’s authorization for your car. 

When walking in the monument, keep a sharp eye on the ground.  Cholla needles can pierce a boot sole and inflict real pain and discomfort.  As always in the desert, keep an eye out for the snakes, especially when the temperatures are moderate and carry plenty of water with you. 


No lodging is available in the Monument. Motels and other lodging are available in the towns of Ajo, Gila Bend and Tucson,

Click on city for. (Rates, availability and reservation online)

Organ Pipe Cactus National Monument


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