penis cactus

Penis Cactus: Trichocereus Bridgesii Monstrose Care

This peculiar (and very real) cactus is actually a nursery-produced cultivar. The trichocereus bridgesii monstrose, the penis cactus, or simply TBM is a columnar cactus species native to South American, La Paz in Bolivia to be more specific.

This popular cultivar is a mutation that is produced through short segmented growth. A growth that can only be propagated using vegetative means.

This plant gets its common name from its undeniable resemblance to a penis. Despite its curious look, the penis cactus was once highly regarded as a sacramental medicine.

In the following, we will talk about trichocereus bridgesii monstrose care and characteristics, and another well-known cactus often associated with it: Bruce’s dragon cactus.

Bruce’s dragon cactus

More about the Penis Cactus

Growing in clusters and branching at the base, it is slow-growing cactus that can reach up to 1’ 4” at full maturity. It has a light glucose green color and stems with short and upright sections. This is the signature of the trichocereus bridgesii monstrose clone A.

The penis cactus does not have too many areolas and spines on its base nodes. The upper part of the stem is smooth with no areolas. The spines grow in groups of four (or fewer than that) with honey to brown color. Be careful about these long spines, as they can grow up to 1 ½ to 2 ½ inches.

Interestingly, we do not know if there is a trichocereus bridgesii monstrose flower. It is unknown that is it a flowering species or not.

There are also other mutant varieties of Trichosurus bridgesii including:

  • A cristate variety
  • A variegated variety
  • Two variants of monstrose growth, clone A and clone B (which is the very penis cactus)
  • A clone that has both monstrose and cristate growth
  • Another clone that shows both monstrose and variegated growth
trichocereus bridgesii monstrose care

Bruce’s Dragon Cactus

Bruce’s dragon cactus is actually a beautiful trichocereus bridgesii variety with broader ribs. And due to these broad ribs, it tends to have relatively few ribs (mostly 4 to 6). Similar to many others, Bruce’s dragon cactus comes from South Australia.

Bruce’s dragon cactus is known for showing a “melting” look from time to time. This look tells us that it is (at least partially) mutated in a way.

Trichocereus Bridgesii Monstrose Care

Growing penis cactus is actually quite easy, both indoors and outdoors. Here is what you need to know about penis cactus care:

  • Water: In trichocereus bridgesii monstrose care, remember that this actually prefers more water than most succulents. In fact, its water needs are really more like ‘normal’ plants than most other cacti. Let the soil dry out between each irrigation and it will do just fine.
  • Light: If grown outside, Bruce’s dragon cactus and the main verities need full sun. However, during hot summers, these cacti can suffer from sunburns. To avoid this problem, grow your penis cactus in light shade. And if grown indoors, provide this plant with bright and some direct light. During winter, place it in a cool and bright spot. Stop watering and fertilizing over the winter to encourage winter dormancy as well.
  • Temperature: This cold-hardy plant can handle temperatures as low as -12 °C or less. Another good news is that they are not as sensitive to warm weather as many other cacti.
  • Soil: Any well-drained sandy soil mix is suitable for penis cactus care.
  • Feeding: During the trichocereus cactus growing season (or other varieties), apply fertilizer each month using a balanced fertilizer.

Keep an eye for common problems trichocereus bridgesii monstrose care as well. Avoid overwatering, as they are susceptible to fungal diseases which show themselves as black rotted spots. Damp soil mix in cold periods also leads to the same problem.


Whether you have a trichocereus bridgesii monstrose long form or a Bruce’s dragon cactus, you can use these tips to grow a happy and healthy plant. Happy cultivating!

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