Saguaro: Savvy Water-Saver

Saguaro cacti really do save water. But they don’t do it like most people think–store it up like a water-tower. You can’t poke a hole in a saguaro and watch the water pour out into a bucket.

Saguaros are about 70 years old when they develop 'arms'

Saguaros are about 70 years old when they develop 'arms'

We had our first monsoon storm the other night. Parts of Mesa got three inches of rain, parts of Phoenix, two inches. That’s more than we got in all last year’s monsoon season. When it rains that hard, saguaros make the most of it. Saguaros have vertical pleats. The pleats serve all sorts of purposes–structure, strength, and the power to expand when water is available.

When the plant is dry, the pleats are close together and thin. Give it a bit of rain, and the plant sucks up the water, the pleats expand like an accordion about to play a polka, and the water is stored for the coming dry days.

Saguaros are protected in Arizona. The one on the left happily soaked up

Saguaro pleat

Saguaro pleat

on the monsoon water, which you can see better in the close up on the right. Because they are protected, there are strict laws about moving them for construction.

The photograph below shows a thinner cactus, one that is still waiting for a good soaking. The Phoenix area has an average of 106 days of temperatures over 100 degrees in the summer, the last one occurring about September 26.

saguaro with bird

saguaro with bird

–Quinn McDonald is a writer and certified creativity coach who is currently moving to the Phoenix area. She took the top two photographs, but the one with the bird on the arm is from science.hq.nasa.gov