PC (Predominant-Cultivar) San Pedro Cactus: A Simple Guide

What is PC Trichocereus?

If you've ever done a deep dive into san pedro cacti, chances are you've encountered the term PC San Pedro, or PC Trichocereus. This mysterious plant is often sought after for it’s ornamental beauty, but has caused quite a stir among experts and hobbyists alike, and is a source of quite a bit of controversy. But what exactly is PC Trichocereus, and why is it so significant? In this guide, let's delve into the history, appearance, and unique characteristics of this plant.

What Does PC Mean?

What does PC mean exactly? No, a PC San Pedro is not a “politically correct” cactus, it’s what is called the “predominant cultivar”. Predominant meaning the most frequent or common, and cultivar meaning a plant variety that has been produced by selective breeding. So, the PC San Pedro is just the most common and widespread variety of San Pedro cactus that exists in the United States. It doesn’t make it any better or worse than other cacti, it is just very popular.

PC San Pedro group

The History & Origins of PC Trichocereus

Controversies and debates have sparked among experts about PC Trichocereus classification and origins, and many emphasize the need for DNA testing to settle these discussions. Some experts think it's closely related to a collection made by Friedrich Ritter, known as Trichocereus riomizquensis. But again, without DNA testing these claims remain speculative. 

In parts of the USA, like California, this clone is very common around parks, schools, and gardens. It's so common that it's become the face of Trichocereus and San Pedro in some areas.

Trichocereus riomizquensis

Trichocereus riomizquensis (Trichocereus.net)

PC San Pedro: The Good, Bad, and Ugly

So why do people want the PC San Pedro so much? Why has it become the predominant cultivar?

Why People Love PC:

  • It thrives in various conditions.
  • It is resistant to drought and overwatering.
  • It is a fast grower and quick to propagate.
  • It forms a lot of offsets.
  • It makes great grafting stock.
  • It has value as an ornamental plant in landscapes.

Why People Dislike PC:

  • There remains a lack of clear origins for this plant.
  • Some say that it is not a “true pachanoi”
    • Because it doesn’t always have the pronounced  v-notching and because it displays white hairs instead of brown, contradicting flower morphology from many textbooks.
  • It’s even been called “pachanot” because of a speculation from a botanist named Keeper Trout.
  • Some say it’s overrated because it has become so commonplace.
    rows of pc san pedro cacti

Either way it’s generally accepted and labeled as “San Pedro” and that’s what you can expect to find at your local garden centers.

How to Identify a PC Trichocereus

Now that we have a background on PC Trichocereus let’s look at the physical characteristics for identifying this plant.


  1. PC San Pedro are light to dark green, to potentially glaucous blue in color with towering columns that can quickly reach 10-20 feet tall. 
  2. They have a medium Thickness in the spectrum of Trichocereus, with a sawtooth rib profile to them.
    PC San Pedro Cacti
  3. Their spines are on the shorter side, and tend to be golden-brown to grayish
  4. They have a tendency to form many offsets/branches from their base,.
  5. And they have White flowers with white hairs (Different from Trichocereus pachanoi, which tends to have black or brown hairs.)
PC Trichocereus Flowers

Context is always important to keep in mind because these features can vary based on the conditions of the plant. You may or may not see certain features, but the most reliable indicators are going to be flower morphology and a reliable source. At the end of the day it’s best to take this all with a grain of salt, and while you can trust reputable sources to properly identify their plants there will always be an inherent uncertainty to some degree. 

What’s Considered Non-PC Trichocereus?

Now that we know how to identify PC San pedro, what are considered non pc? Non PC San Pedro are:

  • Pachanoi that are seed grown
  • Other trichocereus species such as bridgesii, peruviauis, or scopulicola, including hybrids
  • ‘Landrace’ varieties of San Pedro, such as Huancabamba, Torres y Torres, and Chauvin de hunter
New Zealand San Pedro that is non-pc


The best characteristics to assess as non-pc are: the prominent v-notching, differences in spine color, spine length, and ultimately flower morphology.

Wrapping up the Mystery

The PC Trichocereus is like the enigmatic character in a thrilling novel. Its origin, classification, and features are topics of intense debate and fascination. But one thing's for sure – it's a unique and intriguing cactus that continues to captivate cactus lovers everywhere. Remember to approach discussions with an open mind and rely on reputable sources for information.

Whether you're an expert or just starting your cactus journey, the world of PC Trichocereus offers endless exploration and intrigue. And who knows? Perhaps you'll be the one to unravel its mysteries!

Key Takeaways:

  • The PC San Pedro is the most common and widespread variety of San Pedro cactus that exists in the United States.
  • The exact history of the origins of PC San Pedro remain unsure.
  • People love PC San Pedro because it is a resilient and fast growing plant that is sought after for ornamental purposes.
  • People dislike PC San Pedro because of its debated history and sometimes inconsistent physical characteristics.
  • Physical characteristics that define the PC San Pedro: green skin, medium thickness, short golden or grey spines, tendency to offset from it's base, and white flowers with white hairs.
  • The most reliable indicators of PC Trichocereus are going to be flower morphology and a reliable source.
  • Non-PC Trichocereus are seed grown pachanoi, other species of trichocereus,  hybrids, and landrace pachanoi.