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How To Tell How Old A Saguaro Cactus Is: 3 Questions To Ask Yourself

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When I moved from Baltimore to Phoenix, I had no idea how much I would miss all the trees and foliage that grew back at home. Deep mysterious lakes, rushing rivers, and ceiling to floor greenery with lush mountains were the norms for me.

Having to move to a city in a desert with an entirely distinct kind of natural beauty was, without a doubt, the largest culture shock my family and I experienced on our first year in Phoenix.

Well, several months into my adventures here, I noticed that something had slowly shifted inside me. Suddenly, I wasn’t scouring the landscape for trees as I drove through the Valley of the Sun.

The only thing that demanded my special attention now was tall and prickly things filled with character. Yes, you’re right; my obsession with trees was slowly replaced with an obsession with saguaro cactuses. This was around the same time I started wondering how to tell how old a saguaro cactus is.

To say the answers to my question surprised me would be an understatement, and that’s why I decided to create this detailed guide on several tricks you can employ to tell how old a saguaro cactus is.

With that in mind, to better answer that question, we’ll take a look at several FAQs (Frequently Asked Questions) regarding the ages of the saguaro cactus.

As a general rule of thumb, note that the best way to determine the age of a saguaro cactus is to start by measuring its height and estimate how long it usually takes saguaro cactuses in similar environments to reach that height. Most varieties of the saguaro cactus, for example, will reach an average of 40 feet tall after approx. 200 years.

Allow me to elaborate using the FAQs below.

How To Tell How Old A Saguaro Cactus Is
Cactus Garden – via Flickr

How To Tell How Old A Saguaro Cactus Is?

At What Age Do Saguaro Cactuses Start To Flower?

A considerable portion of saguaro cactuses’ growth happens in the summer; around the same time monsoon rains introduce high levels of moisture. This period is optimum because it’s also usually warm enough for the cactuses to grow. If the area the saguaro cactus is growing is experiencing multiple-year droughts and sparse summer rains, the cactus won’t grow very much.

With that in mind, in Saguaro National Monument, for instance, summer rainfall hits an average of 16 inches per year. As such, saguaro cactuses in this region have been proven to hit flowering age in approximately 30 years.

Another example is the Organ Pipe National Monument, which experiences an average of just 9 inches of rainfall annually. Here, saguaro cactuses take twice as long as they would’ve taken in Saguaro National Monument to bloom. Some plants have even been reported to bloom for the 1st time after 75 years.

What Is The Growth Rate of Saguaro Cactuses?

According to the Arizona Sonora Desert Museum, a saguaro cactus’ growth in its initial 15 years is extremely slow. That explains why most saguaros that are grown out in nature from seed rarely make it past infancy. Some of them are killed by the winter freezes or hot sun, others are washed away by running water after heavy rains, and others are eaten by animals while still youngsters.

Most saguaro cactuses that make it past this initial growth phase do so because they had successfully established themselves in the shelter of protecting rocks, bushes, and even large trees.

With that in mind, regarding how you can tell the age of a saguaro cactus from its growth rate, note that a 15-year-old saguaro cactus might be just under 1 foot tall, whereas a one-year-old saguaro cactus will usually be just one-quarter of an inch tall.

After the 15 years have passed and saguaro cactuses have attained some size, they start to grow faster as their roots also begin to extend out further wide and deep from the plants to gather more water (particularly during rainstorms.) At this point, saguaro cactuses will also develop larger stems that allow them to manufacture and store more food through photosynthesis for more and faster growth.

Note, though, that everything we’ve touched on so far in regards to the growth rate of saguaro cactuses only talks about those growing in the wild.

Saguaro cactuses getting regular watering sessions with drip emitters and in landscaping situations will usually grow much faster compared to their counterparts in the wild. If the saguaro cactuses are in a nursery condition, expect their growth rate to accelerate even further, thanks to optimum fertilizers and watering sessions.

With that in mind, under nursery conditions, seedling saguaro cactuses can reach up to 6 inches in less than three years and sometimes even bloom in anywhere from 15 to 20 years.

That said, note that poted saguaro cactuses that aren’t awarded tender loving care will tend to grow even slower than those growing in the wild. Improper caring habits include not giving sufficient fertilizers or watering sessions to the saguaro cactuses.

How Long Does It Take Saguaro Cactuses To Mature?

The National Park Service estimated that most saguaro cactuses live between 150 and 200 years and will usually reach anywhere from 50 to 60 feet once fully grown. Older saguaro cactuses will also tend to have grown more arms or branches. However, do not use branching to tell how old a saguaro cactus is because this process is unpredictable.

Saguaro cactuses in places with more rainfall will usually see more branching occurring.

>> Related Post: How To Tell How Old A Cactus Is (4 Important Tips)

Final Thoughts

It now feels like I’ve lived around these Saguaro cactuses in Phoenix my all life. Over that time, I’ve also seen these magnificent beasts in all their different sizes and shapes, including some that have grown to be as heavy as several tons and more than 80 feet tall.

What’s more? After learning that the saguaro cactus will commonly live to be approximately 200 years old, I came to the educated conclusion that the different sizes and shapes of these plants must represent the saguaro cactuses at various stages of their lives.

I hope the guide I’ve shared above has equipped you with all the details you need to learn how to tell how old a saguaro cactus is just by looking at it or slightly inspecting it.