Saguaro -- an engineering marvel

This is a cross section (sort of dried out) of a saguaro cactus (Carnegiea gigantea). The cut off pieces in a ring around the center of the plant stem are actually long very strong poles that run all the way up through the cactus stem called saguaro ribs. Here is a photo of a mature saguaro:


This particular plant has an abnormal arm growth called fasciation or cresting, which may be caused by a bacterial infection, or mite or insect attack on the plant tissue.

The saguaro blossom is the state flower of Arizona. The flowers provide food for a variety of flying animals and insects, including bats and the Whitewing Dove. The construction of the stem with pleats, allows for expansion and contraction depending on the water supply. The roots system spreads out from the plant in a circle, extending out approximately to the height of the plant. During periods of increased rainfall, the plant will adsorb as much water as possible, enabling it to survive long periods of drought. Adult saguaros may weigh as much as 12,000 pounds.

The ripe fruit is edible and tastes quite good. The plant's ribs and fruit have been used for centuries by the native Americans of the Southwest. Although it is the tallest cactus native to the U.S., there are cactus in Mexico, the Cardon (Pachycereus pringlei ), which grow much taller.

Since I grew up in the Phoenix area, I always remember seeing saguaro cactus. I used to amuse me to see tourists stop their cars and stand next to a saguaro to get their pictures taken. I have grown a saguaro from a small seedling only about three inches high for many years. The plant is now about four feet high and will take another fifty years to grow arms. I do not plan on outliving the saguaro.

As cactus go, they are extremely visible but not very dangerous. The spines are really tough and could conceivably make quite a hole in your skin, but you would have to be sleep walking to run into one. I do not recall ever hearing about anyone who got stuck with a saguaro spine.