Saquaro Wobbling

Q. After I spoke with you yesterday, I went outside and took some pictures of my saguaro. Upon closer inspection, I found some of those dreaded black spots you mentioned at the base of the plant. I also attempted to move it and it wobbled back and forth. I'll be taking it out this spring if you think that is what should be done.

A.
Sagaro Shouldnt Wobble

That “wobbling” you mentioned is bothersome to me. These plants need to be firmly anchored into the soil if they are to remain upright. In nature the roots of the saguaro may spread out eight times its height. This provides firm anchorage in the soil. To get this kind of anchorage, water needs to be applied deep and infrequently and at large distances from, and including, the plant.

Plant Neighboring Desert Plants

            This can be done in several ways. One method is to grow other plants coming from the same climate zone at different distances from the saguaro. Irrigation supplied to these plants will be enough to encourage the roots from the saguaro to spread out. Enough water should be applied the first couple of years about a foot deep. As the saguaro gets taller, this water should be applied so it percolates 2 to 3 feet deep.

Water Once in Awhile

            Another method, and one that I really prefer, is to take a hose on a mechanical timer and inexpensive sprinkler and turn the water on for one hour. I would do this on both sides of the saguaro about 6 feet from the trunk with the water reaching the saguaro. Do this three times; in early spring, once in the summer, and again in the fall. This timing encourages root growth of desert plants but avoids the growth of Bermudagrass. If you see some Bermuda growing, whack the top off with a hoe or shovel as soon as you see it. Do this once a week until it’s gone.

Look for Black Spots

            The “wobbling” and appearance of black spots on the outside of the saguaro tell me that it’s probably getting watered too often and the water applied is too close to the trunk. Those black spots or “cankers” indicate an internal rotting of the tree.

            You can find out more about this and what to do by “Googling” the words “University of Arizona” and “problems and pests of cacti”. Scroll down and a link should appear that will take it to their publication on how to control diseases of agave,cacti, and yucca and what to do about it. Make sure you use a sharp and sanitized knife.

            Your call on whether to remove it or try to rescue it.