Native to mountainous regions of Ecuador and Peru, the San Pedro Cactus is a stately branching columnar that can get 20 feet high and 6 feet in spread. Although in habitat it grows at elevations of 5000 to 9000 feet, it has nevertheless acclimatized to the heat of the lower deserts of our southwest and it is a popular landscape plant here. It is reported that it can produce cream colored flowers up to 9 inches in diameter, though I've yet to see any on mine. Echinopsis pachanoi is sacred to some South American Indian tribes and reportedly contains small amounts of mescaline.
     I planted some of this from cuttings about 12 years ago and though it grew OK it never flowered for me. I pruned this one severely last year and potted up a bunch of cuttings. I'm going to try to grow some where it gets more sun. Then maybe I'll get flowers. The stems on mine never exceeded a couple inches around, but I've seen some around town that get 4 or 5 inches thick.