Mexican Fence Post Cactus Steroids?

The GIANT Mexican Fence Post cactus in my front yard is the main organic feature of my property. I thought that the previous owners had splurged and planted a massive cactus. No. I chatted with a neighbor yesterday who told me that his puny 6 ft tall cactus and the Canadian snow bird's across the street 8 ft tall cactus and my 20 ft tall giant were all the same size when planted 5 years ago by the builder. My somewhat obstreperous neighbor (he owns hot rods that he's built, and expresses strong opinions without reservation) told me how my home's original owner used to be out in the mornings, "puttin' somethin' on it that made it grow so damn big!"

So perhaps my predecessor here in west Phoenix had concocted some brew of plant steroids, tweaked Just Right. This weekend, I'll have to remove several new buds before they turn into Large Arms that make some of the main stalks lean even more precariously than they are leaning now.