Saguaro Cactus Resources

2023 Summer Heat

My saguaro is losing arms. Is it because of the heat?
Cooperative Extension researchers are trying to find out. Samples have been sent to a University of Arizona plant pathology lab to check for bacteria or fungal infections. During Arizona’s last extreme heat wave in 2020, many urban saguaros died with a bacterial infection. This year, seemingly healthy saguaros are losing arms or collapsing. Fallen saguaro arms have a poor prospect of rooting and growing into a new plant. 

What should I do if I have a large saguaro?
A large saguaro can weigh several tons. Don’t park your car under the cactus, or sit or store things under a saguaro. If you are planting a new saguaro, place it away from buildings, parking areas, pools, or seating areas. 

Selecting and Planting Cactus
Transplanting Cactus

Saguaros are easy to cultivate in most of southern Arizona but must be planted properly.

They should be placed where their weight won’t pose a hazard if they fall.

Plants 5 feet or taller are very heavy and should be moved by professionals.

Problems, Pests and Diseases

Diseased saguaros usually can’t be saved, but the cactus can tolerate scarring.

Problems may include improper planting, failure to establish, and physical damage.

A rot disease called bacterial necrosis is common.

Habitats, Wild and Cultivated

Saguaros are easy to grow in southern Arizona, but do you have the right spot?

They can prosper in a range of well-drained soils containing sand, silt or loam, including gravelly and rocky soil.

They do not do well in poorly-drained clay soils.

Life Cycle of the Saguaro Cactus (Carnegiea gigantea)

The tallest cactus in the U.S. and tallest Sonoran Desert plant - sometimes taller than 60 feet

Up to 35 Years

Saguaros often mature in the shade of mesquite, paloverde or ironwood trees. 

They grow about 1-1.5 inches per year, but this can vary depending on location and rainfall.

Young saguaros grow as a single trunk that produces flowers at about 35 years

Reproduction 

The saguaro blossom, Arizona's state flower, usually is open for one day only and is pollinated by bats, birds and insects.

Seeds are spread by birds and other animals that eat the fruit

Each fruit can have up to 2,000 seeds.

Maturity

After about 50-70 years, depending on conditions, saguaros may begin to grow arms.

An old saguaro may produce more than 20 arms.

Saguaros continue to grow and add arms until they die, usually between 150-175 years. Some live more than 200 years.