Penis Cactus 101

How to Take Care of a Penis Cactus

The penis cactus is what is known as the monstrose form of the Bolivian Torch Cactus, or Trichocereus bridgesii. It’s quirky appearance makes it a fun addition to any garden or a great gift for those with a sense of humor. In this guide we’ll go into care basics for this cactus like light, soil, water, and more, so that you can see just how low maintenance this plant can be. Because who wouldn’t want a penis cactus?

Lighting Requirements for a Penis Cactus

The penis cactus wants lots of bright light so find a spot by a window where it can soak up the sun and grow. If you can’t find a spot that lets in enough light then adding a grow light can be greatly beneficial to this plant.

Proper Soil & How to Repot

This cactus needs a very well-draining soil mixture that has a healthy amount of perlite or pumice added to it. These plants tend to not like excess moisture so this will really help you out in the long run.

Breaking up the roots

Consider gloves when handling this cactus to protect yourself from its spines. Gently remove your penis cactus from its previous container and break up the soil as best you can to give the roots space to grow out. Take a pot partially filled with soil, and place your cactus inside, filling in  more soil all around, and firmly tucking it in for support.

tucking in soil around sides of penis cactus

If you have a hard time getting around the spines then a small tool can help to push the soil in. When you’re done feel free to add top dressings to finish up the arrangement and make it look complete, but also to add extra support to your plant! You can find this pot as well as many kinds of top dressings here.

How & When to Water a Penis Cactus

To check when your penis cactus needs water you’ll want to make sure that it looks wrinkly and feels very soft to the touch. It should have some give and feel a little deflated rather than feeling firm. The soil should also be completely dry, which you can check with your hand or a tool like a wooden skewer. It should also feel pretty light!

dry skewer = soil is dry
No soil stuck to skewer = soil is dry!

When it’s ready, give your cactus a long full watering, making sure that any excess water is draining out of the bottom of the pot. Then you will wait for the soil to dry out completely again before watering.

This cactus goes dormant in the colder months, so you should water it very infrequently then — only when it looks very shriveled.

Identifying Health Issues and Common Problems

A healthy penis cactus will have a bright vibrant green color, firm stems, and a smooth texture. Size, length, and shape can be a little irregualr, but a fully grown penis cactus will be about 2-3 feet tall with a similar diameter akin to a shrub. A few small, light brown blemishes might appear here and there on the skin but that is normal.

A common problem for this plant is fungal issues. Keep an eye out for circular, brown or black spots that can be a sign of these infections. And be on the lookout for dark splotches, splitting, and rotting for signs of overwatering.

small circular spots = fungal issues
small, circular spots = fungal issues
splitting = overwatering
splitting due to overwatering

Fungicide, well-draining soil, good airflow, and fertilizing in the growing season will help to keep your penis cactus happy and healthy. And a plant in good health is less prone to systemic issues forming in the long run.

Temperature & Humidity

The penis cactus prefers a warm, dry climate. If you’re growing penis cactus outdoors, be sure to protect it from frost, as this can cause damage. But otherwise it should be nice and comfortable in your home.

It’s also important to keep your penis cactus in an area with good airflow. As we mentioned before, they are more prone to issues that arise from too much moisture.

Pest Control for Penis Cactus

The penis cactus is most commonly attacked by mealybugs, scale, and snails, and should be treated as soon as you spot them. Isopropyl alcohol and SlugGo are good treatment options, as well as keeping these plants free of weeds.

pest damage on penis cactus
signs of pest damage

How to Propagate Penis Cactus Successfully

Propagating a penis cactus can be done through stem cuttings! To do this, take a sterilized cutting tool and cut straight across a healthy stem at the node. These are the areas that new stems are growing out of. Make sure to leave areoles, the spots where the spines are coming from, on the original plant so that new offsets can grow out.

cut off an offset

Allow the cut end to callus and form a rough surface for a few weeks, and then plant it in well-draining soil. Then wait a few weeks for roots to develop before watering.

penis cactus replanted in soil

Rare Flowers of the Penis Cactus

Flowers are actually extremely rare for the penis cactus. If it does bloom, it will bloom large white night-blooming flowers that are covered in white hairs on the outside. 


With these straightforward care tips, you can easily cultivate a healthy and vibrant penis cactus in your home or garden. This quirky and low-maintenance plant is sure to bring a touch of humor to your collection, and a smile to your guests’ faces. By ensuring proper care for this plant, your penis cactus will thrive and become a delightful conversation piece. Should you have any questions or need further advice, feel free to reach out.

Key Takeaways

  • The penis cactus is a monstrose form of the Bolivian Torch Cactus, Trichocereus bridgesii.
  • Make sure to give this plant lots of light!
  • Use well-draining soil with plenty of perlite or pumice mixed in when repotting.
  • Water only when the cactus feels deflated and the soil is completely dry.
  • A healthy penis cactus will have a vibrant green color, firm stems, and a smooth texture.
  • Fungicides, well-draining soil, good airflow, and fertilizing in the growing season will help to keep your penis cactus happy and healthy.
  • Can be propagated through stem cuttings, but make sure to leave areoles on the original plant that the cuttings are being taken from.