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San Pedro Cactus Identification


san pedro cactusSan Pedro Cactus (Trichocereus pachanoi) is a large succulent which normally grows in the shape of a column, and is particularly successful in areas of full sun, even when very little water is available. It has a very tidy compact growth pattern, and is extremely low maintenance, which makes it an ideal choice around pool areas, and is one reason for its tremendous popularity in the Southwest. The cactus was named after the Catholic saint, Peter, who was the first pope and the traditional guardian of Heaven. It has been used in religious rituals and divination practices by Native American populations for nearly 3000 years.

Geographic data

The San Pedro Cactus belongs to the Cactaceae family, which is native to the northern Andes Mountains of Peru, as well as Ecuador and Colombia. The climates of these countries frequently range toward cool temperatures which the San Pedro can tolerate, and it can also withstand a large amount of water, as long as the surrounding soil is rich in humus or is sandy and fast-draining. Soils which are heavy and routinely moist however, will cause the San Pedro to fail. In the countries of its origin, the San Pedro cactus commonly achieves heights near 20 feet.

Color and shape

Echinopsis pachanoi ranges from a medium-colored green to a darker green, and occasionally sports a bluish tinge when grown in shade or when exhibiting new growth. As the arms of the plant grow vertically, they take on a cylindrical shape and exhibit between four and nine ribs, which have small spines grouped together along the ridges. The San Pedro cactus has spines which are fewer in number and smaller than most varieties of Echinopsis. Garden enthusiasts and plant lovers everywhere appreciate the Echinopsis for its distinctive growing pattern emulating a candelabra, with multiple stalks growing out from the base.

Flowers and Fruits

The San Pedro Cactus has very decorative and aromatic blossoms, with white flowers fully emerging at dusk as long 8-inch trumpet-shaped flowers. These will stay open all night long, during which time they are pollinated by bats, and in the daytime, bees will also visit to pollinate the flowers. Although it is rare, the San Pedro occasionally produces a red-colored fruit which is edible. It has a moderate growth rate which is faster than most succulents and other cacti, and it has a tendency to get top-heavy. When this occurs, portions of the plant will simply topple over and break off, followed by new growth which emerges from the remaining stub, with sprouts then popping up in abundance.


There are small amounts of the psychoactive compound Mescaline found in the San Pedro cactus, and this had value to native Peruvians, who used it in ancient ritual cleansing ceremonies for hundreds of years. It is still used by some South American natives for divination purposes, and as a traditional medical treatment for conditions such as high blood pressure and heart problems. It has been used recreationally as a hallucinogenic drug by many artists and writers, notably Aldous Huxley, who wrote 'The Doors of Perception' while experimenting with mescaline.

Other Considerations

While it is perfectly legal to grow San Pedro cactus as a garden plant for its decorative and ornamental value, is illegal in the United States to grow the plant for the purpose of extracting mescaline from it. Possession of San Pedro cactus is illegal in cases where it is clear that the purpose of possession is to produce mescaline or mescaline-based compounds.