Native to central Mexico, pachycereus marginatus is an interestingly spined columnar to 18 feet tall with stems 5 inches across when grown well in the landscape. The plant branches at the base eventually producing a clump several feet wide. Wild specimens are usually much smaller, only 5 feet, and plants cultivated in pots usually top out at a couple of feet, stems to two inches thick. The spines and aeroles on the 5 to 7 ribs are interesting in that they form very close together producing a white felty stripe down each rib. It is a very pretty effect. In Mexico cuttings are sometimes planted along the borders of properties as a kind of live fence, hence the common name. Plants that receive enough light and water produce pinkish green flowers followed by red or yellow fruits in spring.
    Twelve years ago I took a cutting of one of these and put it in the ground. It has grown and each year the newer branches get fatter. But it's never flowered. Probably too much shade where it's planted. I'm going to try planting some where it gets more sun this year.

A large stand at the Shriners in Tucson

A potted specimen stems 3 feet tall

A closeup of the interesting spination