What Is a Penis Cactus and How Do You Grow It?

The “penis cactus” is a succulent named for its unique appearance of short, columnar stems with a rounded top. This plant is a naturally mutated form of a cactus from the Trichocereus genus, native to the Andes Mountains. Its unusual growth pattern makes it a conversation piece and a sought-after specimen for collectors of peculiar plants.

Identifying the Penis Cactus

Scientifically known as Trichocereus bridgesii monstrose, the term “monstrose” refers to a genetic mutation that causes the cactus to grow in an abnormal, lumpy way. This mutation disrupts the plant’s primary growth point, leading to its distinctive, segmented, and often branching form.

The most sought-after cultivar is Clone B, the true short-form “penis cactus,” prized for its compact, clumping stems that rarely exceed a few inches in height before branching. A less common variant, Clone A, is a long-form type that produces much longer, more cylindrical stems that can sometimes twist or revert to standard columnar growth.

Psychoactive Properties and Legality

The parent species, Trichocereus bridgesii (Bolivian Torch cactus), is a member of the San Pedro family. These cacti have been used in Andean ceremonies for their psychoactive properties, derived from the alkaloid mescaline. As a monstrose variety, the penis cactus can also contain mescaline, though concentrations are highly variable.

In many countries, including the United States, it is legal to own and cultivate Trichocereus bridgesii monstrose for ornamental purposes. However, federal law makes it illegal to knowingly cultivate or process the plant for consumption or to extract mescaline. Prospective growers should research the specific laws in their state or country.

Penis Cactus Care Guide

Light

This cactus thrives with several hours of direct sunlight each day, which helps maintain its compact shape and healthy green coloration. An ideal location is a south-facing window for indoor plants or a garden spot receiving at least six hours of bright, direct light. Insufficient light will cause the plant to stretch in a process called etiolation, resulting in weak, pale, and elongated growth.

Soil

To prevent root rot, this cactus requires a substrate with excellent drainage so its roots never sit in water. A commercial cactus and succulent mix is a good starting point, but many growers amend it with materials like perlite, pumice, or coarse sand. The goal is to create a gritty, porous medium that allows water to pass through freely.

Water

Use the “soak and dry” method for watering. This involves thoroughly saturating the soil until water runs from the container’s drainage holes, then allowing the soil to dry out completely before watering again. During the active growing season in spring and summer, water every couple of weeks. In the dormant winter months, watering should be reduced to once a month or less, as overwatering is the quickest way to kill this plant.

Temperature

This cactus is well-adapted to a range of temperatures. It prefers warm conditions during its growing season, ideally between 70-90°F (21-32°C), and can tolerate high heat with adequate airflow. While somewhat cold-hardy, it must be protected from frost. If grown outdoors in a region with freezing winters, it must be brought inside when temperatures drop below 32°F (0°C).

Propagation Techniques

Propagation is most effectively done through cuttings, which creates new plants that are genetically identical to the parent. Use a clean, sharp knife to remove a segment from the main plant, making the cut at a joint between sections for a cleaner separation.

Set the cutting aside in a dry, well-ventilated area for several days to a few weeks. This allows the cut surface to form a callus, a hardened layer that protects the raw tissue from rot when planted. After a firm callus has formed, place the cutting upright with the callused end about an inch deep into a pot of dry, well-draining cactus mix. Do not water for the first couple of weeks to allow roots to begin forming.

Common Growing Issues

The most frequent problems for this cactus are directly related to its care. Root rot results from overwatering or soil with poor drainage, while etiolation (stretching) is caused by insufficient light. Refer to the care sections above for prevention.

Pests can also be an issue. Spider mites and mealybugs are the most likely culprits, feeding on the plant’s juices and causing discoloration. Manage them by spraying with insecticidal soap or using a cotton swab dipped in rubbing alcohol for direct removal.