Back to the Garden – Cristate Saguaro, An Eyeful of Magic
Sheilah Britton, Pinal County Master Gardener
The Sonoran Desert is full of surprises—javelina families sharing a prickly pear cactus, hawks on the arms of saguaros, water rushing through arroyos after a rain, a chorus of coyotes howling at dusk, cactus flowers coloring the desert in spring. But when you come upon a saguaro whose familiar posture, form, and balance have taken on abstract expressionism, you know that nature has dealt you an eyeful of magic.
The saguaro, Carnegia gigantea, appears only in the Sonoran Desert, mostly in Southern Arizona, but also in Northern Mexico and parts of California. According to Don Swann, a biologist with the National Park Service, “Cristate saguaros or crested saguaros form when the cells in the growing stem begin to divide outward, rather than in the circular pattern of a normal cactus. This mutation results in the growth of a large, fan-shaped crest at the tip of the saguaro’s main stem.”
The first recorded sighting of a crested saguaro might have been a photograph of the species taken at the Arizona territory display during the 1893 World’s Fair in Chicago. The specimen wouldn’t have survived the Windy City’s winter, and anyone who witnessed it has been gone for decades. Still, the unusual saguaro continues to garner both wonder and delight when one appears as a curiosity in the Sonoran Desert.
Scientists have yet to agree on what causes a saguaro to crest, and the reason for this anomaly is still in question. Many suggest it is caused by weather—frost or lightning strikes. But more recently, the odds have fallen on internal chaos—genetic mutations or hormone disturbance.
In a recent study, researchers at Arizona State University and the University of Arizona successfully sequenced the saguaro’s genome. “We can now identify the genetic regulatory and metabolic networks responsible for their unique form and physiology and their unique form of photosynthesis,” says Martin Wojciechowski, a professor with ASU’s School of Life Sciences.
Although the rare crested saguaro has puzzled scientists for decades, its scarcity makes it challenging to research. U of A’s Dario Copetti, who was part of the team that sequenced the saguaro’s genome, explains, “If we tackled it (crested saguaro) from a genetic point of view, we would need to collect DNA from several crested saguaros and compare them to many non-crested saguaros—requiring substantial funding, labor, and research.”
A recent 2020 saguaro census at Saguaro National Park estimates around two million saguaros in the park, but only recorded one crested saguaro in the 22,000 that were mapped and measured. “There are many more than that known in the park, but the census is based on random plots,” says biologist Swann. “It’s too small a number to draw inferences, except to say that it indicates they are pretty rare, indeed.”
Crested saguaros can be found in Tucson and the surrounding area. There are fine specimens at the entrance to the Arizona Sonoran Desert Museum, as well as in the gardens of Tohono Chul and Catalina State Park, but the greatest pleasure comes from discovering one while hiking in the open desert or watching one form in your own neighborhood.
SaddleBrooke/SaddleBrooke Ranch Master Gardeners are volunteers trained under the auspices of the University of Arizona, Cooperative Extension, Pinal County. We offer educational programs and classes to residents of our communities.
Need advice or have questions about your own garden? Send an email to [email protected] Include your name, address, phone number, and photos of your issues.
Please visit our website at extension.arizona.edu/saddlebrooke-master-gardeners.
Demonstration Day Set for February 26
Zann Wilson, Pinal County Master Gardener
Join your SaddleBrooke/SaddleBrooke Ranch Master Gardeners for a demonstration day on Saturday, Feb. 26, from 1 to 3 p.m. at SaddleBrooke Ranch. We will show you the best tools, techniques, and products to satisfy a variety of gardening needs. Demonstrations will include best tools, best container management, frost and sun cover materials, pruning tools and techniques, and best supplemental soil amendments and mulches. Also, learn about monarch butterfly patterns and support. Ask your Master Gardener all those burning questions about your own landscape. Sign up for plant help assistance. Just walk by and browse our tables and topics. Find us at the SaddleBrooke Ranch Community Garden. The garden is located at the end of Egret Trail. Take Arroyo Vista, left of the gatehouse, and follow it to Egret. Continue to the very end of the drive at the garden. See you on Feb. 26.
Join The Discussion
Zann Wilson, Pinal County Master Gardener
Join your SaddleBrooke/SaddleBrooke Ranch Master Gardeners on Thursday, Feb. 17, at 1 p.m. in the SaddleBrooke Ranch Sol Ballroom for 2021: A Pretty, Weird Year in the Sonoran Desert with Amy Belk, manager of Pima Prickly Park, Pima County’s Native Plant Nursery, located in Oro Valley. Amy has worked in horticulture for more than 20 years and has observed the horticulture industry from many different angles, but she feels most at home serving and interacting with the community and sharing her excitement about plants with others.
Join us for a discussion about what we are seeing in our native plants after a weird year of droughts and floods, superheat and superblooms, and unprecedented foraging from both insects and animals. With a focus on our native plant communities, we will talk about the situation both before and after our substantial summer rains, how things are looking through winter, and what we might expect to see going forward.
Policy changes at SaddleBrooke Ranch have caused us to ask for your support. Since we are a not-for-profit organization, we are unable to absorb the cost of a $1 per chair setup fee. We ask you to consider donating a dollar to our program in an effort to address this fee. Collection baskets will be at the entry door. Thank you in advance for your generosity, and we very much look forward to seeing all of our garden friends for this reentry to in-person programming.
If you have questions, contact Zann Wilson at [email protected]