If you live in the Phoenix area you might notice the abundance of saguaro cacti decorating our neighborhoods, our roads, and store-fronts. Undoubtedly, they are an iconic image of Arizona. But in recent years I have noticed an increase in saguaros that have fallen over, lost arms, or died. 

How do Saguaros get to Your Front Yard?

Most, if not all, of the saguaros that you see in the Phoenix area have been replanted and moved to that location. Doing this is very difficult. Saguaros have a root system that stretches out as long as they are tall, with a taproot reaching five feet or more. When they are replanted they are not as rooted to the ground as they would be if they grew from that spot. Factors like erosion and flooding can cause saguaros to become uprooted and fall over.

What Factors Affect the Lifespan of a Saguaro?

In the wild saguaros can live to almost 200 years! In the desert saguaros can be killed by old age, lightening storms, wild fires, strong winds, and freezing temperatures. When saguaros are replanted however, they are more likely to be killed by falling over, as their roots cannot adequately anchor them to the ground. Additional factors like overwatering and high temperatures can also kill saguaros.

Climate Change and the Saguaro

An effect of the continual warming of our planet is more destructive storm fronts and wildfires. Thus, as time progresses, the chance for a saguaro to be killed by weather events increases. Also, high carbon emissions will slowly raise the temperature of the globe, effecting not just saguaros but every living thing. In urban areas, climate change is amplified by higher levels of pollutants in the air, which can negatively affect saguaros.

Heat Islands

The city of Phoenix is a heat island – which is an urban area that is warmer than its surrounding environment. Man made structures like sidewalks, roads, and buildings absorb heat and keep it trapped in the city. Unlike the desert, where nighttime temperatures can drop to below freezing in the winter, urban areas retain their heat. Long periods of high temperature can weaken and eventually kill saguaros, especially when there is no cool night time temperature for balance.

Source: “The Effect of Rapid Urbanization on the Physical Modification of Urban Area” by Kamyar Fuladlu, Müge Riza, and Mustafa Ilkan

Care and Keeping of Saguaros

If you have a saguaro in your yard, there are many ways to ensure that it will live for years to come. One thing to be aware of is how much the cactus is watered. Saguaros are desert plants, they don’t need to be connected to irrigation, but they benefit from some supplemental water during drought. It is also important to ensure that water does not sit around the base of the cactus, as it can lead to it falling down. For instance, avoid planting a saguaro near a roof, where rain can runoff and collect. Cactus fertilizer or nutrients sprinkled around the base, while not necessary, can promote health and growth when used in moderation.

Signs of A Healthy Saguaro

Telling the difference between a healthy and unhealthy saguaro can be easy. The most obvious thing to look for is if the cactus stands up straight. A cactus that leans could be at risk at falling over – with some common culprits being too much water or not enough sun. Sometimes a saguaro can get sunburned, and that will be evident from dark brown patches on its skin. They can also have bacterial infections. These usually start from the ground up, with the skin turning light brown and then black, with thick cracks. I have seen this many times on saguaro in my neighborhood, and is easy to spot. When making your saguaro sightings it’s important to note cactus health, pictures help too!

How can you help?

The first thing to do is stay educated on saguaros and their role in our desert ecosystem. My project focuses on education of the community as well as creating a way for the community to log health of saguaros.

Log Your Saguaros

One of the goals of my Gold Award Project is for the community to be able to log any saguaros in the Metro Phoenix area, detailing its location and health. To do this I’ve created a project on the program iNaturalist to allow others to log their sightings, while also taking into account anyone in the area who logs a saguaro.

What is iNaturalist?

iNaturalist is a website and app that is a joint initiative of the California Academy of Sciences and the National Geographic Society which allows anyone to create an account and log sightings of flora and fauna in their area. It creates citizen scientists who can provide valuable data to researchers on population and biodiversity.

Click the link to see our iNaturalist project page, you will need a free iNaturalist account to log reports: https://www.inaturalist.org/projects/save-our-saguaros-a-gold-award-project

If you do not wish to create an account but still want to help log saguaros feel free to email me a picture of the specimen, along with location, and general observations at: sossaguaros@gmail.com

Current Logs

Below is a current map of the saguaros that have been logged by citizen scientists in the Metro Phoenix area. While some saguaros might have already been logged, feel free to add on general observations to already established logs, so we can keep track of the health of these cacti!