The Saguaro cactus species in Arizona

Within Arizona’s Tucson Basin is The Saguaro National Park.  This park provides the ideal conditions for sustaining dense stands of the famous saguaro cactus.

saguaro cactus at The Saguaro National Park

saguaro cactus at The Saguaro National Park in Tucson

Saguaros are found exclusively in the Sonoran Desert.

**The most important factors for growth are water and temperature. If the elevation is too high, the cold weather and frost can kill the saguaro. Although the Sonoran Desert experiences both winter and summer rains, studies show that the Saguaro cactus obtains most of its moisture during the summer monsoon season.

Saguaro National Park

saguaro cactus in Arizona

There are dozens of varieties of cacti;  short, tall, stout, delicate but none quite as magnificent as the Giant Saguaro cactus.

Quick Saguaro Facts:

  1. Saguaros have one deep tap-root but most of this cactus’ roots are 4-6 inches deep and span out as far as the desert plant is tall.
  2. The saguaro is the largest cactus in the US.
  3. After the saguaro dies its woody ribs can be used to build roofs, fences, and parts of furniture.
  4. The Giant Saguaro can live to be 200 years old.

In the Sonoran desert the saguaro cactus has a boundless variety of towering and many armed shapes.

the saguaro cactus in arizona

the saguaro cactus species in AZ

Water makes up 75 to 95 percent of the saguaro cactus’ weight.  During periods of drought the pleats of the saguaro cactus contract.  During Arizona rains the saguaro expands as it soaks up moisture.

saguaro cactus with fruit

saguaro cactus close up

Saguaros, like many desert cacti, grow excruciatingly slow.  Arizona cactus experts estimate that a forty-foot tall saguaro is about 150 years old.  Arm buds begin to appear when the saguaro is 75 years old.

the saguaro arms

the saguaro arm buds

Many saguaros now standing in cactus forests germinated in the mid-1800s.

saguaro cacti over 100 years old

saguaro cacti over 100 years old

To survive their early years, saguaro seedlings must be sheltered from the elements, whether it be under the canopy of other plants or in the crevices of rocky outcrops.  Saguaro seeds can be deposited in droppings of birds roosting on branches of shrubs and trees.

nurse tree

young saguaro cacti under a nurse tree

Lightning, powerful winds, harsh winter freezes and the rotting of dead tissue kill saguaros.  The saguaro’s woody ribs stay on the desert floor until they are consumed by termites or decay and return to the soil.

dead saguaro cactus wood

woody spine of the dead saguaro cactus

The saguaro is not currently listed as threatened or endangered. Arizona has strict regulations about the harvesting, collection or destruction of the saguaro cactus.

dead saguaro cactus

dead saguaro cactus

Saguaro cactus can be found in southern Arizona and western Sonora, Mexico.

Related saguaro facts and photos:


Saguaro Cactus Pictures – Saguaro National Park – desert blooms and flowers

One of Arizona’s most Majestic, Lovable desert cactus has got to be The Saguaro, (Carnegiea gigantea) Giant Cactus. On my last trip to Saguaro National Park I could not help but fill my camera with photos of the King of Cactus. Being aware of the history and incredible internal design of  The Arizona Saguaro, I’m filled with honor and respect as I walk close to the Giant Saguaro’s that are over 150 years old and standing tall.  The saguaro is the largest cactus in the United States. In 1931 the pure white blossom of the Saguaro Cactus was designated as the state flower for Arizona.

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Saguaro National Park

The saguaro cactus (Carnegiea gigantea) is one of the defining desert plants of the Sonoran Desert. These desert cactus are large, tree-like columnar cacti that develop branches (or arms) as they age.  These arms generally bend upward and can number over 15. Saguaros are covered with protective spines, white flowers in the late spring, and red fruit in summer. The Saguaro Cacti mainly grow in the Sonoran Desert of Arizona.

Saguaro Cactus can not tolerate freezing temperatures in the winter, this is what limits their range.

Photos of Saguaro Cactus at the Saguaro Nat Park in Arizona.

Saguaro FACTS:  Saguaros are a very slow growing cactus. In Saguaro National Park, studies indicate that a saguaro grows between 1 and 1.5 inches in the first eight years of its life.  A 10 year old plant might only be 2 inches tall. Saguaro can grow to be between 40-60 feet tall (12-18m). When rain is plentiful and the saguaro is fully hydrated it can weigh between 3200-4800 pounds.

Arizona Saguaro

Saguaro Cactus on Mica Peak

Here you can see how big a Saguaro Cactus is. This is NOT the tallest.

Driving through Saguaro National Park, I took this picture of the Saguaro cactus at the bottom of Mica Mountain. Monsoon rains have made everything green.

Mica Mountain Saguaro National Park

The saguaros cactus roots are only 4-6 inches deep and travel out as far from the plant as it is tall. There is one deep root, or tap root that extends down into the ground more than 2 feet. A Saguaro Cactus can gather enough water through its efficient root system, during a significant rain, to last a year if necessary.

Older Saguaro Cactus with birds nesting inside

What are the holes in the Saguaro Cactus? The gilded flicker and Gila woodpecker excavate nest cavities inside the saguaro’s pulpy flesh. When a woodpecker abandons a cavity, elf owls, screech owls, purple martins, finches and sparrows may move in.

In the picture above you can see the holes in The Saguaro made by the Gila woodpecker. Below in the pic you can see the finches and sparrows that have made nests in the Giant Saguaro.

When a saguaro reaches 35 years of age it begins to produce flowers.

Birds nesting in the Arizona Saguaro Cactus

Cactus Wrens are common birds that live in the holes (nests) of the Saguaro Cactus.

Saguaro Cactus Flowers bloom, then turn to fruit

The Saguaro cactus Bloom, Flower.

The Saguaro flowers bloom after sunset. If it is a good year, the flowers may completely encircle the stem tips. At the top of the flower tube is a dense group of yellow stamens. The saguaro cactus has more stamen on its flower than any other desert cactus. Nectar accumulates at the bottom that attracts birds, insects and bats. A Saguaro can only be fertilized from a different cactus – cross pollination. Not all the flowers bloom at the same time, unlike the Queen of the Night flowering cactus. Only a few bloom each night awaiting to be pollinated and close by late morning. If the Saguaro flower has been pollinated by the bats, birds or insects, a red fruit will begin to form. The beautiful desert show, occurs over a month to 2 months. From living in this area I have to say it is hard to determine the exact dates but end of April to beginning of June would be notable.

The Saguaro Cactus Flowers/Blooms, if POLLINATED, will turn to red fruit.

Mica Mountain with Saguaro Cacti

A dead Saguaro next to an older one.  Native Americans had many uses for the woody ribs of the cactus.

Because the majority of a desert saguaro cactus is made up of water, an adult plant may weigh 6 tons or more. This tremendous weight is supported by a circular skeleton of inter-connected, woody ribs.  The number of ribs inside the plant correspond to the number of pleats on the outside of the plant. After the saguaro dies its woody ribs can be used to build roofs, fences, and parts of furniture.  See the photo above I took of a dead Saguaro Cactus. The holes that birds nested in, called saguaro boots, can be found among the dead saguaros. Native Americans used saguaro boots as water containers long before the canteen was available.

The Saguaro Cactus is pictured next to a biker so you can compare the size.

While a saguaro cactus begins to age, its growth rate varies depending on climate, precipitation and location. It is known that the period of greatest growth in a saguaro cactus is from unbranched to branched adult. Here at Saguaro National Park, saguaro branches normally begin to appear when a saguaro cactus reaches 50 to 70 years of age. An adult saguaro is generally considered to be about 125 years of age. It may weigh 6 tons or more and be as tall as 50 feet. The average life span of a saguaro is probably 175 years of age. Experts have estimated that a Saguaro Cactus with more than 5 arms can be 200 years old.

A nurse tree for a young Saguaro Cactus, Yellow Palo Verde Tree gives off nitrogen

Young saguaro cacti can be very hard to find because they grow under the protection of a “nurse tree”, most often a palo verde, ironwood or mesquite tree. As the saguaro continues to grow, its much older nurse tree may die. In the Saguaro Cactus picture I took above, the nurse tree is a Yellow Palo Verde. The nurse trees release nitrogen in the soil which the Saguaros and other desert cacti, like prickly pear cactus, use to grow healthy and strong.

Even when the Arizona Saguaro cacti grow in their normal form, they rarely grow symmetrically. Saguaros sometimes grow in odd or mis-shapen forms. The growing tip occasionally produces a fanlike form which is referred to as crested or cristate.  Some speculate that it is a genetic mutation. Others say it follows disturbance of the growing tip by mites, fungi (e.g. white rusts), and other biological factors. The exact nature of the disturbance is unknown, but it appears to involve the growth regulators in the Saguaro cactus.

Captured in this photo is the rare Cristate Saguaro Cactus.

Though these crested saguaro cacti, Carnegia gigantea forma cristata, are rare, over 25 live within the boundaries of  The Saguaro National Park. Biologists are not sure why these Saguaros grow this fan-like shape. To us that visit and take pictures of these rare Arizona Sonoran Desert Cactus, we only see the beauty of the Cristate Saguaro.

This picture is the Crested, Cristate, Fanlike rare Saguaro Cactus from Arizona

I took this photo of the rare Saguaro at the Arizona Desert Museum in Tucson.

Arizona has strict regulations about the harvesting, collection or destruction of  The Arizona Saguaro Cactus. It is illegal to harm a Saguaro in Arizona. During building or construction, precautions must be taken to move every saguaro that may be affected.

** different spellings used are saquaro, saguara, sahuaro, saguro.