Demystifying the Saguaro

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Pair of Peregrine Falcons nesting in a Saguaro.

Okay; so not everything in Arizona revolves around occulted mysteries orchestrated by the hidden hand of an international cabal hellbent on global domination, but that doesn’t mean that a drive across town can’t be just as interesting. As humans, we tend to look at our everyday surroundings with less curiosity and wonder that we would a foreign landscape if we were to go on vacation. This is one of the easiest ways to spot a tourist from a local. Children too have a natural curiosity and tend to look deeper into things than adults, that is unless they’ve been anesthetized with a cellphone. But still, this is why some of my favorite people to have out on tour with me are children and locals. While the good questions always come from the kids, I get to watch the faces of the locals as I peel back the urban veil and introduce them to a parallel dimension they have been unknowingly coexisting with their entire life.

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One of my favorite Saguaros for no particular reason. This particular fellow is the topic for many a tours.

Today we are talking about the Saguaro cactus. Instantly recognizable it is undoubtedly one of my favorite plants to cover while on tour. While naturally commanding attention the Saguaro seems a product of something out of a Dr. Seuss book. Not only are people naturally curious about this desert giant, but the more I talk about its mysteries the more I discover as well. I can honestly say that I’ve spent entire tours standing around a single Saguaro and still did not have enough time to fully disclose all its wonderment.

Is there a more iconic symbol of Arizona than our stately Saguaro? Please note that I use the word “our” with a specific intent as these treasures belong to all who live among them, not in the sense of ownership mind you, but stewardship. Dotting the hillsides, freeways, and neighborhoods of Phoenix, Saguaros define the boundaries of the Sonoran Desert. Phoenix sits on the northern edge of the Sonoran Desert, and the Sonoran Desert is the only habitat in the world for this species of cactus.

unnamedThe name “Saguaro” Pronounced (Sah-wor-O) not (Sah-gwar-O) was first given to this columnar cactus in 1856, from Spanish/Mexican origin. The name is an interpretation of an unknown Native American word for the cactus, perhaps Yaqui, Yavapai, or Piman; but no one seems to be sure.

An impressive denizen of the Sonoran landscape, these cacti can span hundreds of years, withstand the worst of droughts, and tolerate with amusement 120-degree temperatures, all the while growing from the side of a rocky cliff. The waxy white blooms are Arizona’s state flower and mark the coming annual monsoon rains.

Saguaro fruit
Saguaro fruit

In each Saguaro’s lifetime, it will bare millions of seeds in potential offspring, yield thousands of pounds of nutritious fruit, and provide shelter in a symbiotic relationship for hundreds of birds. Today these giants are seen as an icon of the American Southwest and locals are lucky to have one growing on their property. But it wasn’t long ago Saguaros were used by indigenous peoples for food, tools, and building material. The myths, legends, and stories surrounding these giant desert sentries are woven into the very fabric of the Sonoran desert and those who call this place home.

Design

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Saguaro skeleton dot the desert but this is a particularly special one as it has maintained its stature without decaying.

Yes, design. Of all the plants built to withstand the extreme desert conditions of southern Arizona, the development and adaptations of the Saguaro are the most impressive. Ribs, pith, hide and root make up the four basic components of the Saguaro. This unique system allows the Saguaro the flexibility to quickly adapt to desert extremes.

  • Ribs – Think of this as re-bar within concrete. The ribs start off as a wooden trunk-ish structure at the base of the cactus but quickly separate out into spaced support “beams” and can become quite long and somewhat flexible without losing their strength. These ribs are the support system for the cactus.
  • Pith – The pith of the cactus is found both within and outside the ribs. It makes up the bulk of the body of the cactus and provides the ability to store water and transfer heat. Think of the pith as an extremely firm sponge working in conjunction with the ribs as a flexible support system, not unlike a high rise building. Only this support system transfers water, nutrients, and heat.
  • Hide – This is the outside of the cactus. It is called a hide because it is extremely thick for a plant. It offers the protection needed to deal with the harsh Sonoran desert sun. The hide is about 15% thicker on the south-facing side of the cactus than any other side. This is due to the Arizona sun dropping 28.6 degrees into the southern sky during the winter months. Because of the increased exposure, the Saguaro has developed a thicker hide on that side. This is one factor taken into account when transplanting them. If the Saguaro is re-planted with the previous south facing side facing any other direction, the Saguaro will soon burn its newly south facing skin and die.
  • Roots– The roots of the Saguaro cactus are without a doubt the most efficient root system known on the North American continent and are capable of transpiring over 1000 gallons of water annually. It is a two root system comprised of a taproot and radial roots. The taproot anchors the Saguaro somewhere between 3-5 feet deep while the radial roots, doing little in the way of stability, grow out as far as the cactus is tall and are only a couple of inches below the surface of the ground. This allows for more efficient water absorption during the rainy seasons.

Structural Engineering
The magic of our mighty Saguaro lies with its vertically running pleats. Those “V” shaped grooves running the length of the cactus are so awesome that I refer to them on tour as its “superpower.” They serve many uses and exemplify drought thriving perfection.

  1. They allow the cactus to expand and contract with the rainy seasons and dry seasons. The corrugated pleats form a series of “V’s” which
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    Note the shadowing on the backs of the pleats. Also, note the shade provided by the spines.

    have the ability to stretch with the absorption of water. In a single year, the Saguaro is capable of sucking up and transpiring a little over a thousand gallons of water and can absorb around two hundred gallons in a single week.

  2. They provide needed shade. The pleats, with the spines on the edges of the “V” provide for a self-shading system. When the cactus is in full sun, it receives around 50% exposure at any given time. Next, take into account the shade provided along the curvature of the cactus shading the backsides of each pleat. This would bring the sun exposure down to around 45%. Next the spines on the outside of the “V’s” provide for further shading bringing it down another 5-10%. Lastly, each individual arm shades the main spike of the cactus at some point during the day providing even more shade. This being said, a Saguaro in full sun in only receiving at any given moment no more than roughly 40% direct sunlight.
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    Vertical pleats shed oncoming wind.

    Stability. For years people couldn’t figure out how these giant cacti remained standing up and not blow over with the monsoon rains. Remember that they can store hundreds of gallons of water and their root system is extremely shallow. With weights reaching upwards of 8,000 pounds and winds often reaching 30-40 mph during the monsoon season, how do they remain standing? The secret is in the “V”. It has been discovered that as a gust of wind first makes contact with the cactus it is diffused as it passes through the spines on the outside edges of the “V’s.” Next, this diffused wind blows to the back of the “V” where it spirals back out forming an opposing circular vortex just a few inches off the cactus. This vortex pushes back against the oncoming wind redirecting it to the sides. What little wind that does get through gets diffused up the vertical pleats. IS THAT FRIGGING COOL OR WHAT? This means that the Saguaro sheds about 75% of oncoming wind and that up to a point, harder the wind blows the more stabilizes the Saguaro becomes within its self-generated vortex. Hence, “superpower”.

Range

This one is easy. The Saguaro cactus grows only in the Sonoran desert which is found only in southern Arizona and northern Mexico. This desert, unlike any other desert on earth, enjoys two rainy seasons, The winter rains which take place February through March, and the Monsoons which occur in the heat of the summer, July, and August. These rains are spaced exactly six months apart which allows the cactus to absorb enough water to sustain its self until the next rain. This unique rain pattern coupled with the extremely high temperatures of summer and the freezing temperatures of winter (yes, it does freeze in the desert) are necessary triggers to the Saguaro’s life cycle. Attempts have been made to transplant and establish Saguaros elsewhere, but all attempts have failed. It seems that Saguaros have already adapted and specialized to their home here in the Southwest.saguaro2

Something else I find quite interesting; If one overlays a map of the range of the Saguaro cactus with that of the ancient Hohokam (The culture who once inhabited southern Arizona) they will find an exact match. This illustrates how important these cacti were to the ancient Hohokam and their descendants who depended on them for survival.

Common questions

How long does it take for a Saguaro to get that big?

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Here is a great example, Papago Park was once known as Saguaro Park but all the Saguaros died due to human encroachment.

There is an educated guesstimation formula for this. 1 inch the first five years. 6 inches by age ten. One foot by age 15. After this 2-3 inches a year, though not necessarily always. First arm between 50-70 years old, but not always. They live to around 200-250 but sometimes older. They grow to around 30-40 feet usually but not always, some have reached 70 plus feet. Scientists use the spines for dating and estimate dates based on the pollution levels trapped in the spine at the time the cactus produced it. Sorta like a hair sampling people. Scientists also use old photos. As simple as that sounds, cameras have been around for two hundred years now and there were plenty of photos taken during the days of the old west. Many Saguaros survived development and the photos are compared to the still living specimen.

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Elf Owl utilizing a Gila Woodpecker nest.

What are all those holes in the sides of them?

Birds nests. The holes you see in the main spike and arms of the Saguaro are habitat which has been pecked by one of two birds. The Curved Bill Thrasher and the Gila Woodpecker. These two desert dwellers peck a hole into the side of a Saguaro, the cactus then secretes a sap which hardens and forms whats known as a boot, and it’s within this boot that they build their nest. Stationed safely above the coyotes,

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Peach-Faced Love Birds utilize the ready-made homes all across Phoenix.

bobcats, badgers and other predators who would rather see them as dinner these nests maintain a 15 degree on average cooler temperature than the temperature outside the cactus. No doubt these nests are the higher end condos of the Sonoran Desert feathered community. These nests also play a larger role as we’ll discover later in this article. What’s cool is, the Gila Woodpecker will build 3-4 nests a year in order to attract a mate, each time he will abandon the old nest and leave it for other birds.
One can observe almost any bird of the southwest in one of these boots that is capable of fitting into it, and this habitat is a primary reason southern Arizona realizes at least some of approximately 50% of all the bird species in North America during the winter months.

5-cent-cactus-fullI see Saguaros along the roads of Phoenix with 2×4’s holding them up. Whats that about?

These are recently transplanted cacti. When a Saguaro cactus is transplanted it is supported for the first couple years by three or four 2×4’s which are placed at 45 degree angels to the ground. These supports allow the root system time to re-establish and stabilize the cactus. It is illegal to kill a Saguaro for any reason so they are often simply moved. Even if you happen to own a Saguaro you can not destroy it, though I can’t imagine why anyone would ever want to as a fully grown Saguaro cactus fetches upwards of $8,000. Owners who wish for their cactus to be removed are required to contact the county and give them up to three months to remove the cactus.  I can recall landscapers and cactus movers knocking on my door at lease once a month offering to buy my Saguaro from my front yard.

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Saguaro/nurse plant relationship.

Where are all the baby Saguaros?

This is one of the lesser known mysteries of the Saguaro and not as straight forward as one may imagine as a Saguaro has a few different stages of development. The first five years as a seedling, the Saguaro will grow only one inch. During this time it must remain under the protection of what is known as a “nursery plant”. In fact a Saguaro requires a nursery plant to grow under if it is survive the first few years. A nursery plant is any plant which protects the Saguaro seedling from the harsh sunlight and wintertime frost. Any plant can fulfill this role but it is usually one of the the multitudes of smaller bushes (Sages, Brittle bush, Jojoba, snake broom, etc) which the Saguaro finds its self nestled under. For under these little bushes one will find the soil a little moister for a little longer following a rain. These protracted moisture levels provide the water necessary to germinate. They also better fully conceal the Saguaro seedling preventing frost damage, or frost death in this case. The second five years a Saguaro cactus will grow to about 6 inches. By this time he is becoming a bit tougher and able to withstand some of the harsh desert environment. Somewhere around year fifteen he will have grown an entire foot tall, toughening its hide and will no longer require its nursery buddy.

The most perfectly symmetrical Saguaro cactus you will ever see.
The most perfectly symmetrical Saguaro cactus you will ever see.

What determines how many arms a particular Saguaro has?

The Saguaro will continue to grow at least 35 more years before it is able to grow it’s first arm. This will usually occur between 50 and 70 years of age. After which it can grow as many arms as it likes, as often as he likes. These arms start out as little round protrusions on the side of the cactus and at the end of a year will look like a spiky green tennis ball is stuck to it’s side. From this point they will continue to grow at the same rate as the rest of the cactus. But what determines how many arms a particular cactus will grow? The short answer is, nobody knows. Over the years there have been many theories but a consensus has yet to emerge. Some of those theories include.

  1. They grow arms to balance themselves out to keep from falling over. Much the same way a tree will correct its self if damaged and right its self again. Whereas this is a popular theory it has been both prove
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    Balancing out?

    n and disproved. Strangely it seems that it may sometimes be the case, but not always.

  2. Predetermined genetics. The theory that certain strains or lineages of cacti already posses the genetics which determine their general or potential appearance. Simply put, they are hardwired to look the way they do.
  3. Environmental. It is believed by some botanists that a Saguaro may be “triggered” to spur out more arms during times of drought. Sort of a defense measure for dryer micro climates within the Sonoran Desert or even longer climate fluxuations. More arms means an increased ability to store water and this equates to survival in times of drought.
  4. Combination of all above theories.

The Saguaro Forest

Saguaro forest north of Fountain Hills, AZ
Saguaro forest north of Fountain Hills, AZ

This is a really cool phenomenon and occurs when growing conditions are perfect for the Saguaro and many examples of these can easily seen north of Phoenix before hitting the 3000 foot elevation mark. The next time you are approaching the town of Black Canyon City pay attention to the Saguaros on the sides of the hills, there will be hundreds of them. There are also many beautiful stands on the Bee Line highway between Fountain Hills and Payson. Although these are far from the only ones in the desert, they are the most easily seen for most people who can’t access the back country of Arizona.

This Saguaro forest looks to be south of Phoenix near the border.
This Saguaro forest looks to be south of Phoenix near the border.

But there is something deeper going on here as well. Remember the bird nests way up high in the Saguaros? Well when you have hundreds of Saguaros in close proximity, you have hundreds and hundreds of bird nests. A city of birds if you will, all living in a neighborhood of “cactus condos”. Now here is the cool part, these birds go out to forage and feed daily. This act in turn helps to reforest and re-vegetate the surrounding desert. This becomes a symbiotic win win for the birds and surrounding area, the Sonoran Desert always seems to be a little healthier around a Saguaro forest.

Ethnobotany of the Saguaro

Native harvesting Saguaro fruit.
Native harvesting Saguaro fruit.

As you can imagine the Saguaro was used by all ancient peoples who lived in its vicinity for food, shelter, tools, alcohol, and even navigation.

While the flesh, or pith of the Saguaro is not eatable, the fruits are. In fact they are the only cactus fruit which lacks spines, and if you’ve ever harvested cactus fruit you know this is an AWESOME thing. These fruits become ready just about the time the monsoon rains hit and are a welcome food source toward the end of summer when there has been nothing fresh for months. I won’t bother to list the tribes who collected this fruit as you can imagine included every one them. Different tribes had different customs and ceremony for this harvest but it was and still is the O’odham people who seem most connected to the Saguaro and its harvest. Huge parties would venture into the desert for this harvest, sometimes it was even a seasonal event, as the parties would harvest north of the now Phoenix area following the Saguaros up in elevation as the season progressed. This provided for a longer harvest as the cacti at higher elevations bloom later and therefore provide fruit at a later date than the cacti in valleys below. The seeds, pith, and juice of the bright scarlet red fruit was all used and nothing went to waste. As you can imagine there are legends and creation stories surrounding the Saguaro, as well as sacred songs which are still sung during this harvest to this day.

The much coveted Saguaro fruit.
The much coveted Saguaro fruit.

The fruit are produced at the top of each arm and the main spike so getting to these fruits wasn’t the easiest of tasks. To accomplish this harvesters would utilize the ribs of dead Saguaros, lashing them together and tying a cross piece to the tip. This pole was then traditionally used by the men to knock the fruits from the top of the cactus. The women would be waiting for the fruit to drop in teams of two with stretched blankets which were used like nets to catch the fruit before it hit the ground. The ripe fruit of the Saguaro fruit can be very delicate and become ruined if not treated gently. The fruits were then turned over the the elders, who with the help of the children would cut them in half and scrape out the pulp, seeds, and juice for later processing. The seeds were ground into flour while the pulp was spread out and dried. The juice was usually put into clay pots and fermented into a wine which was consumed immediately at the soon to follow harvest celebration.

Preparing for a Saguaro harvest.
Preparing for a Saguaro harvest.

No doubt this was a very special time of year for all peoples of southern Arizona and it is reflected in their stories and histories. The Saguaro was held in such reverence by the Pima people who occupied the Phoenix area that the cactus was often refereed to as the “Saguaro People” when spoken of collectively. The Pima thought of the plants as a tribe and treated with a deserving level of respect. Just as it is illegal to destroy a Saguaro today, so it was a thousand years ago as well.

saguaro-buds-05The Pima believed that after death, men were reincarnated as Saguaros, while women were reincarnated as the arms of the Saguaros. Perfectly logical seeing they were a polygamist society and men often had many wives. It was believed that the good wives a man had in life were the arms that pointed up on the cactus, while any bad wives were the arms which pointed down.

The ribs of the Saguaro were used for constructing shelter, sweat lodges, cot frames, back rests, racks for drying meat, looms for weaving clothing, spears, baby boards, etc. Having an extremely strong weight to strength ratio they are perfect for light construction, furniture, tools, and pretty much anything one could require in a camp.

Weaknesses

While researching this article one book I have said that saguaros are vulnerable to bacteria and yeast infections, which can be carried by the wind or insects. Another book said that sunburn and frost damage cause a skin condition that is sometimes called “epidermal browning” and that is still not fully understood. Yet another book said that a type of moth tunnels into the saguaro, making a kind of black ooze spill out of it. This is called bacterial necrosis. If it spreads inside, the cactus may eventually decay and fall apart. It seems that Saguaros have quite a few enemies in the natural world, but the one danger which presents the most harm to them is humans.

Gunshots holes in the side of Saguaro.
Gunshots holes in the side of Saguaro.

Pretty much any damage one may witness on a Saguaro from about 6 feet and below is man-caused. And not necessarily by anyone who is alive today either. Keep in mind that these cacti live for over two hundred years old. When leaving Phoenix by way of I-17 north, keep a lookout for the Saguaros in the median and along side the highway. Most of the larger ones all have significant amounts of damage, and most of that damage is gunfire. I-17 used to be a stage coach road before it was paved and most of this damage occurred over a hundred years ago in a time when man was not so environmentally conscious.

It is worth noting that saguaros are not in danger of extinction, but at the same time live only within the conditions offered by the Sonoran desert. This means that while they are not immediately threatened this is the only habitat for them in the entire world. There is some concern however as the southwest continues to grow. This being said, the best protection these cacti have received has been the continuing education, especially to the young, and the enforcement and prosecution of those who would steal these cactus off the desert for profit. Being nearly impossible to police and monitor thousands of miles of back country, extremely sever punishments have been imposed for the theft, destruction, or injury of these cacti.

Hug a cactus, show you care. We have to protect our state treasures.
Hug a cactus, show you care. We have to protect our state treasures.

Whereas the rumored 25 year prison sentence is nowhere near the actual punishment imposed for molesting a Saguaro, it is classified as a class four felony and carries with it a mandatory 1 to 3.75 year prison sentence. Other crimes listed as class four felonies are: Negligent homicide, Kidnapping without physical injury, and structure arson. Wow, that’s still pretty heavy legislation for the protection of a plant species.

Thoughts

Please keep in mind that we only scratched the surface of this awesome Arizona legend, and there is much more we didn’t explore here that I save for my tours. It is my hope that this article has deepened your interest in our precious Saguaro or awakened your thirst to learn more about the Sonoran Desert and its 2000 species of plants, 200 species of animals, or 2 billion year old geology.

Please don’t hesitate to contact me if happen to be in the Phoenix area and wish to see the desert in a whole new light, I am an independent certified interpretive guide, and rather affordable. In the meantime, if you happen to live in Arizona, the next time you see a Saguaro, please take a moment to walk up and introduce yourself. Note it’s particular age, shape, individual characteristics, and scars. Take notice of the stress rings and track the rainfall for the past 50 years. Note the position of the bird nests, are they on the north or south side of the cactus? Is this particular cactus a summer or winter home? Is this Saguaro at the edge of its habitat and struggling, or located in a prime spot? Look uphill, is it the offspring of another which shed it’s seeds 150 years ago? Perhaps just sit for a spell and see what you can see. As a native Arizonan, practitioner of primitive skills, and life long Sonoran desert botanist I can tell you I learn something new every time I sit down long enough to become invisible again.  

 

And if you read all the way to the end, here you go.  Two extremely rare Saguaros.

Extremely rare "Crested" Saguaro.
Extremely rare “Crested” Saguaro.
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Still trying to figure out what caused this. No idea at this point.

Cory Daniel is a professional certified interpretive guide and writer/researcher who currently lives in the Valley of the Sun.

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