San Pedro Cactus Care: Tips On Growing The Trichocereus Pachanoi

The San Pedro cactus is arguably the most popular columnar cactus in desert gardening circles, Trichocereus pachanoi [try-koh-KER-ee-us puh-KAH-no-ee] gets its name from the hairy (tricho) floral tube.

This Trichocereus (Echinopsis cactus) hails from the countries of Northern Argentina, Bolivia, Chile, Ecuador, and Peru, South America.

pachanoi san pedro cactusPin
Pachanoi San Pedro cactus with dark green stems

In 1974, H. Friedrich and G. D. Rowley merged the genus Trichocereus and Echinopsis (ek-in-OP-sis, referring to a similar appearance to sea urchins).

While the genus Echinopsis pachanoi is currently valid, there’s a push to restore Trichocereus as the sole genus due to irreconcilable differences in the genera.

The plant was cataloged by the American botanist J. N. Rose named the species after Ecuadorian professor Abelardo Pachano.

As a result of its popularity, the cactus (most commonly known as San Pedro) has 25 different common names in Spanish alone.

A few examples are andachuma, gigantón, huachuma, and wachuma. It was consumed for ancient tribal healing and spiritual purposes.

Various Trichocereus species are scattered throughout the Andes mountains, with San Pedro being native to altitudes of 6,600′ to 9,800’ feet.

There are a total of five pachanoi species.

It should also be noted a close relative, the Peruvian torch cactus (Trichocereus peruvianus) is so similar the two species are almost synonymous.

Trichocereus Pachanoi Quick Care Tips

  • Botanical Name: Trichocereus Pachanoi
  • Common Name(s): San Pedro cactus, Huachuma
  • Synonyms: Echinopsis Pachanoi
  • Family & Origin: Cactaceae family, native to Northern Argentina, Bolivia, Chile, Ecuador, and Peru, South America
  • Growability: Easy to grow
  • Grow Zone: USDA zones 8-10
  • Size: Grows up to 20′ feet tall and 6′ feet wide
  • Flowering: Blooms in the summer with white, fragrant flowers
  • Light: Full sun to partial shade
  • Humidity: Low humidity
  • Temperature: Tolerates temperatures as low as 20°F
  • Soil: Well-draining soil
  • Water: Water thoroughly but allow soil to dry out between waterings
  • Fertilizer: Fertilize once a month during the growing season with a cactus fertilizer
  • Pests & Diseases: Susceptible to mealybugs and spider mites, can also be affected by root rot if overwatered
  • Propagation: Propagated from cuttings or seeds
  • Plant Uses: Used in traditional medicine and shamanic practices, also grown as an ornamental plant.

San Pedro Cactus Care and Cultural Requirements

Size and Growth

The Pachanoi cactus is a fast-growing cactus, multi-stemmed plant or small tree growing approximately 5.9’ feet wide and up to 19.7’ feet tall in its natural habitat.

Individual stems range from 2.4″ to 5.9” inches thick and may have between 4 and 8 ribs each. Spines are light brown or dark yellow.

Tall cactus against blue sky.Pin
Photo Credit: Instagram @jaekim_6

It also features numerous spines that can get up to 2 cm long or more.

Given the right amount of moisture, sun, and soil, these cacti can grow up to 1’ foot per year.

The columnar stem ranges from pale green to blue-green, dark green with age with upward-facing areoles.

Flowering and Fragrance

San Pedro buds are pointed and produce a fluted whitish flower in July.

They are night flowering and remain open for the following day, with the fragrant flowers measuring approximately 8.7” inches in diameter.

Green cacti with spines in sunlight.Pin
Photo Credit: Instagram @floragrubbgardens

These flower buds are also produced from the spine clusters along the margins near the top of branches.  

Black or brown hairs and scales cover the fruit, which measures 1.9″ to 2.4” inches long and 1.2″ inches in diameter.

Light and Temperature

San Pedro thrives in direct sun after the first year, although seedlings may suffer sunburn in direct sunlight. 

In general, Trichocereus pachanoi grows well in full sun or light shade during hot summers.

Be sure to gradually introduce a plant overwintered indoors to direct light, as they may get sunburned if transferred directly.

If grown indoors, this multi-stemmed columnar cactus will need additional lighting from grow lights.

A healthy San Pedro can withstand temperatures as low as 50° degrees Fahrenheit (10° C) with the occasional brief dip as low as 15.8° degrees Fahrenheit (-9° C).

This resistance to cold may be bolstered through Valerian flower extract.

It can thrive in USDA hardiness zones 8B to 10B.

San Pedro cactus, ribbed columns, displaying its unique flower structurePin

Watering and Feeding

As with many succulents, this cactus will go dormant in colder months and should be given no water between October and April to reduce the risk of rot.

Seedlings may have a very diluted mix of fertilizer occasionally, but adults are capable of being fed an undiluted concentration.

If you do feed, use a diluted liquid fertilizer and only fertilize during the growing season.

Soil and Transplanting

Tricho cactusi requires fertile, slightly acidic potting soil with good drainage.

A minimum amount of humus works best to reduce the risk of rot.

Green cactus with cobweb, garden background.Pin
Photo Credit: Instagram @bluetowernursery

Seedlings will benefit from a tiny amount of highly diluted fertilizer, although adults can handle larger quantities.

Seedlings may be safely transplanted into pots after one year.

Grooming and Maintenance

  • Tricho cactus may be clipped for grafting or pupping.
  • Be sure to clip 12” inches or more as larger plants grow faster.
  • No other grooming is necessary for a healthy plant.
  • The cactus is also low-maintenance.
  • Be sure the soil is well-drained.
  • A bit of sulfur or diatomaceous earth added to the soil works well as a natural pesticide.

How To Propagate Trichocereus Pachanoi

San Pedro seeds are very small and easy to propagate using the Fleischer technique.

Tall green cactus against a wooden fence.Pin
Photo Credit: Instagram @the.cactus.jones

You will need the following items:

  • Clear glass jars (such as mason jars or salad containers) with lids or use plastic wrap
  • A mix of fine sand and sowing soil (potting soil increases the risk of rot)
  • A spray bottle
  • Seeds verified less than ten years old (within one year are the most viable)

Sowing The Seed

  • Fill the bottom of the container with the potting soil mix.
  • Level the soil and tamp it down gently to provide a stable platform for the seeds.
  • Sprinkle the seeds onto the soil, allowing them to rest on top.
  • Lightly mist the soil with water and cover it with lids or plastic wrap.
  • Place the containers in a sunny area where they won’t have direct sunlight exposure.
  • You may also use an LED lamp of 150 watts or higher. More on growing under artificial light.
  • The ambient temperature should remain between 77° and 86° degrees Fahrenheit (25° – 30° C).
  • Seeds should germinate within 2 to 3 weeks.
  • A seed that fails to germinate in 6 weeks or shows signs of white mold on the seed itself is likely dead.
  • Open the lid and dry the soil out before starting again.
Tall cactus plant in outdoor settingPin
Photo Credit: Instagram @flowers.cactus

You should also open the lid to dry if you see signs of fungus gnats.

Signs of mold in the jar should be rinsed away with the spray bottle, and the jar should be allowed to dry out before reclosing.

Be warned; the market is saturated with poor-quality seeds.

Be sure to check the age of the seed when planning to self-germinate.

The younger they are, the better the chances of successful germination.

Aside from seeds, san pablo cactus propagation can also be done through cutting.

NOTE: Plants easily root from offsets

Pachanoi Cactus Pest or Diseases

All Trichocereus species are susceptible to deadly fungal diseases and infections when overwatered in hot weather.

These include damping off, orange rot, and witches’ broom disease.

Black rot is generally harmless and will heal itself after a short time.

Root mealybugs, scale, and spider mites may also be a problem.

These are safely dealt with using neem oil sprays.

Learn how to use Neem as a drench.

Scale is easily scrubbed off when caught early.

Suggested San Pedro Cactus Uses

As with many succulents in the Cactaceae family (and throughout the Andes and Amazon basin in general), the San Pedro cactus has long been valued by natives for medicinal and religious purposes.

Dense cactus field, green textured pattern.Pin
Photo Credit: Instagram @edavilasoto

In the US, it has become a viable substitute for peyote during hallucinogenic rituals due to the presence of mescaline.

This San pedro cactus flower is highly ornamental and works great in any desert-themed garden setting and an indoor decorative plant.

It also works beautifully as an ornamental in tropical climate gardens and a lovely addition to the landscape.

JOIN Our FREE Plant Care Newsletter 

By entering your email address you agree to receive a daily email newsletter from Plant Care Today. We'll respect your privacy and unsubscribe at any time.