The Trichocereus bridgesii forma monstruosa inermis, commonly known as the Penis Cactus, is a distinctive succulent prized for its phallic-shaped stems. This unusual growth habit makes it popular among plant enthusiasts and collectors. Despite its appearance, the Penis Cactus is resilient and low-maintenance, appealing to both novice and experienced succulent growers. Its slow growth and architectural form add an interesting element to any plant collection.
Essential Care Requirements
The Penis Cactus thrives in abundant light, needing at least six hours of direct sunlight daily. A south-facing window or sunny outdoor spot is ideal. When moving the cactus to a brighter environment, do so gradually over several days to prevent sunburn. Insufficient light causes etiolation, where the plant stretches and becomes pale.
Water using the “soak and dry” method, allowing the soil to dry completely between waterings. Water thoroughly until it drains from the pot’s bottom. During the spring and fall growing season, water more frequently. In winter, the plant is dormant and needs significantly less water. Overwatering quickly leads to root rot.
A well-draining soil mix is essential, preventing water from lingering around the roots. Use a specialized cactus or succulent potting mix, often composed of inorganic materials like perlite, pumice, or coarse sand, for rapid drainage. Adding extra grit enhances aeration. A pot with ample drainage holes is also necessary to prevent waterlogging.
This succulent prefers warm temperatures, ideally between 65°F and 80°F (18°C and 27°C) during active growth. It is sensitive to frost and needs protection from freezing conditions. The Penis Cactus is adapted to dry climates and requires low humidity, making it well-suited for most indoor environments. High humidity can contribute to fungal issues and rot.
During the spring and summer growing season, apply a balanced or low-nitrogen cactus fertilizer. Fertilize sparingly, typically once every 4-6 weeks, following dilution instructions to avoid over-fertilization. Over-fertilizing can cause nutrient burn and damage roots. Withhold all fertilizer during the dormant winter months.
Potting and Repotting
Unglazed terracotta pots are preferred for Penis Cacti due to their porous nature. Terracotta allows for better air circulation and faster evaporation of excess moisture, reducing root rot risk. The pot size should be slightly larger than the current root ball. Drainage holes at the bottom are necessary for proper water egress.
Repot when the cactus becomes root-bound, indicated by roots growing from drainage holes or slowed growth. The best time to repot is early spring or summer, during the plant’s active growing phase, for quicker recovery. Repotting every two to three years is a general guideline, depending on growth rate and pot size.
When repotting, carefully remove the cactus and gently shake off old soil. Inspect roots for rot or damage, trimming affected areas with a clean knife. Place fresh, well-draining cactus mix into the new pot, center the cactus, and backfill with soil, maintaining the original depth. After repotting, wait at least a week before watering to allow damaged roots to heal.
Propagation
Propagate Penis Cactus through stem cuttings. Take a clean, sharp cut from a healthy, mature stem section using a sterilized knife or pruning shears. The cutting should be at least a few inches long to establish roots.
After taking the cutting, allow the cut end to “callus over” before planting. Place the cutting in a dry, warm location away from direct sunlight for one to two weeks, until a dry layer forms. This process prevents fungal infections.
Once callused, plant the cutting upright in a small pot with well-draining cactus mix, burying it deep enough for stability. Do not water initially; wait one to two weeks, then water sparingly, allowing the soil to dry completely between waterings. Roots typically form within several weeks to a few months, after which the new plant can be cared for as a mature specimen.
Common Problems and Solutions
Common pests include mealybugs and spider mites. Mealybugs appear as small, white, cottony masses, while spider mites cause fine webbing and stippling. Manage infestations by wiping pests with a rubbing alcohol-dipped cotton swab, or by applying neem oil or insecticidal soap for severe cases. Regular inspection helps catch infestations early.
Fungal issues and rot are caused by overwatering or poor drainage. Signs include a mushy, discolored base, often black or brown. If detected early, cut away all soft, discolored tissue with a sterilized knife until only healthy tissue remains. Allow the healthy section to callus over before replanting in fresh, dry, well-draining soil to prevent recurrence.
Etiolation, characterized by thin, stretched, and pale growth, indicates insufficient light. Move the cactus to a brighter location, gradually acclimating it to prevent sunburn, for more compact growth. Shriveling or wrinkling stems can signal underwatering. However, shriveling can also indicate root rot if damaged roots cannot absorb water, requiring a root system inspection.