Q. Our saguaro is about 10 years old.  In the last year or so four arms have popped out mostly on one side.  Now the saguaro is beginning to lean and we have propped it up. What do you suggest we do? Even though this picture is not from the submitter I wanted to post it for my friends who are viewing from other countries or part of the USA. Saguaro is not native to the Mojave Desert but to the Sonoran to our south. Even though they can be a bit sensitive to the Mojave winter cold they have done quite well in the lower elevations of southern Nevada. If people will stop putting burlap coats on it for the winter….. A. I would guess your irrigation is too close to the trunk. This concentrates the roots there and doesn’t allow root development further from the trunk for support.             In the wild, saguaros roots are about 30 inches deep near the trunk and spread a distance equal to its height at depths averaging only about 10 inches.  This matting of shallow roots spreading from the trunk is important in keeping the cactus erect.             I would prop it up as you are doing and immobilize the base so it cannot move. Then I would apply water at increasing distances from the trunk. These should be shallow and infrequent irrigations at distances from the trunk equal to at least half of its height.             You can do this by planting other desert plants that require similar types of irrigations in these areas. Water supplied to these plants will help to irrigate the saguaro. You can also do this by handwatering in these areas once a month with a spray nozzle.