Key Features to Identifying the San Pedro Cactus

Here at Sacred Buttons I receive a lot of photos from people asking the question: is this a San Pedro? While many of these people are lucky enough to have one of these sacred cacti, some have more common and less desirable lookalikes. In this article, we delve into the San Pedro cactus's fascinating history and provide essential tips for identifying its distinctive features.

What is the San Pedro Cactus?

The San Pedro (Trichocereus pachanoi) is a large, fast-growing, columnar cactus that contains the psychedelic compound mescaline. Native to the Andes Mountains, specifically in Peru and Ecuador, the San Pedro thrives at high altitudes ranging from 2,000 to 3,000 meters (6,500 to 9,800 feet) above sea level. 

For thousands of years it has been used in traditional shamanic ceremonies and healing rituals by indigenous peoples in the Andes, often in the form of a psychoactive brew called "cimora". This sacred practice is believed to foster a connection with the divine, promote emotional and physical healing, and provide insights and guidance.

The San Pedro got its name from Saint Peter, the Christian saint who is said to hold the keys to heaven. This name signifies the cactus's reputed ability to unlock spiritual insights and divine experiences.

Key Features of the San Pedro Cactus

1. Rib Structure:

• Rib Count: San Pedro cacti typically have 6 to 8 ribs. Although, in some cases they may have as little as 4 and as many as 10. 
• Rib Appearance: The ribs are rounded, run vertically along the length of the stem, are evenly spaced, and can sometimes exhibit a slightly wavy or undulating pattern. The valleys between the ribs are shallow but may appear deeper when the cactus is dehydrated.

2. Color:

• Stem Color: San Pedro cacti range in color from light to dark green and blueish-green. 

3. Spines:

• Spine Length: The spines are short growing up to 2cm in length. 
• Spine Color: Yellow to light brown.
• Number of Spines: Each cactus varies, containing anywhere from three to seven radial spines that emerge from the areoles.

4. Areoles:

• Areole Appearance: The areoles are light colored, often white, and have a furry appearance. Each one points slightly upwards and has a notch or "eyebrow" above it.
• Areole Spacing: They run upwards along the ribs, approximately an inch apart.

5. Growth Pattern:

• Height: San Pedro are capable of growing up to 6 meters tall in the wild.
• Branches: Branches (or pups) sprout along the main stem, but more often grow from the base of the cactus giving the illusion of multiple cacti rather than a branching treelike structure. 
• Growth Rate: They are fast-growing, capable of growing up to a foot per year.

6. Flowers:

• Flower Color: San Pedro cacti produce large, fragrant white flowers.
• Bloom Time: The flowers typically bloom at night and may stay open for a day or two.
• Flower Placement: Flowers emerge from the areoles near the top of the cactus.

7. Texture:

• Surface: The surface of the San Pedro cactus is smooth with a slightly waxy texture, which helps protect it from sunburn and water loss.

Below is a picture of a true San Pedro (Trichocereus pachanoi). Notice the eyebrows above the slightly upward pointing areoles and the wavy side profile. 

Common Lookalike 

One common lookalike of the San Pedro cactus is the PC pachanoi, PC standing for predominant cultivar. Although similar to true San Pedro (Trichocereus pachanoi), the PC variety is more common and contains less alkaloids. This makes it less desirable for ceremonial use. It is however popular for use in landscaping due to its fast growth and ability to spread quickly. This variety is commonly found in nurseries and home improvement stores. Here are some key features to help you differentiate PC pachanoi from true San Pedro.

1. PC lack the notch or "eyebrow" above the areoles.
2. The areoles on the San Pedro point slightly up but the on the PC they point much higher, in some cases strait up.
3. Because of the high pointing areoles on the PC, their side profile is more jagged and sawtooth looking, where the San Pedro is smoother and only slightly wavy. 
4. PC tend to stay more green in color and not adopt a bluish hue.
5. PC flowers develop white hairs around their base, unlike the black or brown hairs found on the San Pedro.
6. PC have very short sometimes almost nonexistent needles. 

Below is a picture of the more common PC pachanoi. Notice the lack of eyebrows and high pointing areoles which give the cactus a more jagged, sawtooth looking side profile. 

Conclusion

By studying this guide and cross-referencing the included photos, you'll develop a solid foundation for identifying these fascinating cacti. The seeds and cacti sold at Sacred Buttons are always true San Pedro (Trichocereus pachanoi) and never the more common PC variety. If you're looking to add a rare cactus with rich history to your collection, explore our selection of sacred cacti, seeds, and growing supplies available here on our website.