Cactus experts tell us there are between 1,500 and 2,000 different species of cactus but in Arizona there’s just one king of cactus: the saguaro. The bloom of this tree-like cactus is the Arizona state flower. Saguaros are only found in the Sonoran Desert and Arizona is lousy with the things. At this point, it should surprise no one that a whole national park was created to protect this prickly prize.

We love the graphic cactus on this sign at an entrance to Saguaro National Park in Arizona.
Exploring Saguaro National Park
Saguaro National Park was founded on October 14, 1994 and is divided into two districts, both easily reached from Tuscon. As you can imagine, it’s dry and hot in this desert landscape so try to visit early or late in the day so you can enjoy some of the short trails within the park without getting scorched.

A cactus closeup in Arizona’s Saguaro National Park.
The Saguaro is the quintessential cactus. If someone told you to sit down and draw a cactus, this is what you’d draw. They’re also a classic symbol of the Wild West right up there with tumbleweeds, ten gallon hats and hitching posts.

Despite its prickly spines, saguaros make nice homes for critters including the Gila woodpecker, as the holes in this one attest.
Every species of cactus is built like a sponge but the saguaro is particularly thirsty. It can hold up to 200 gallons (757 liters) of water for up to a year. The saguaro can shrink or swell by up to 25 percent depending on how saturated it is.

Eric dwarfed by a saguaro cactus in Saguaro National Park in Arizona. They can grow to up to 60 feet (18 meters) tall and can weigh more than a ton.
In the United States, Saguaros are only found in the wild in Arizona and, rarely, in southeast California. Saguaros have also become a popular landscaping plant but many of the saguaros you see in front yards were illegally harvested from protected areas, which is becoming a serious problem.

Saguaros as far as the eye can see.
Saguaros can grow to up to 60 feet (18 meters) tall, however, they may take their sweet time getting there. In dry conditions it can take years for a saguaro to grow just a few inches. In wet years a saguaro may shoot up five feet (1.5 meters).

Not every cactus in the park is a saguaro. Here’s a rebel.
Fully grown and fully saturated, saguaros can weigh up to a ton making them the largest cactus in the United States. Saguaros typically live between 100 and 200 years though experts admit some giants may be even older than that.

We have no idea how birds like this Harris hawk can land on something as thorny as a saguaro but they do it all the time.
The “arms” branching out of a central trunk, which we associate with saguaros, don’t develop until the cactus is many decades old. Some saguaros eventually sprout more than 50 arms. A saguaro without any arms is called a spear.

Saguaros in the afternoon sun in Saguaro National Park in Arizona. The saguaros pictured above without any arms are called spears.

It’s a cactus jungle in Saguaro National Park.

You’ll be in a forest of saguaros in Saguaro National Park but don’t forget to look for other species, like this one, too.

A cactus cluster in Saguaro National Park in Arizona.
Bonus: the Arizona-Sonora Desert Museum
Two miles (3 km) from the Saguaro National Park visitor center you’ll find the Arizona-Sonora Desert Museum and we highly recommend it. Yes, there’s no shortage of cactus in the park but this living museum presents a huge variety of species and lots of cactus-loving critters in a great setting. A 2 mile (3 km) stroll takes you through a meticulously curated zoo and botanical garden celebrating the best the Sonoran Desert has to offer including 40,000 types of cactus and other desert plants, many of them rare or endangered, and desert animals ranging from cougars to butterflies.

A flowering cactus at the excellent Arizona-Sonora Desert Museum near Saguaro National Park.

A flowering cactus at the excellent Arizona-Sonora Desert Museum near Saguaro National Park.
One last prickly issue
You will notice that we have worked really hard to avoid using the plural of cactus in this post. That’s because we couldn’t decide which one to use. According to that know-it-all Merriam-Webster, cacti, cactuses, and cactus are all correct.
Here’s more about travel to US National Parks & Monuments
Here’s more about travel in the USA
I remember seeing these cactuses several years back for the first time. I didn’t know how huge they were. I guess I should base my knowledge on more than what The Roadrunner shows me ;)
The spines on that small white cactus look particularly sinister … great pics!
I have been to AZ and seen many of these all over the state. However, once in Tucson I experienced something related to a cactus that I had never tried. I was introduced to a prickly pear (Opuntia) margarita! I was a little concerned on how it would taste, but it was really good. Just a suggestion to try one sometime. I don’t think you will be disappointed.