Triangle Cactus (Acanthocereus tetragonus): Care And Propagation

Triangle Cactus

Acanthocereus tetragonus commonly known as triangle cactus is a tall columnar cactus. This plant can attain a height of 2-7 m. Since this is a tropical plant, it requires bright sunlight. The evergreen nature of this plant has extended its usefulness as a landscape plant.

Triangle Cactus

The triangle cactus can be grown both indoors and outdoors. Whether you grow it indoors or outdoors, a minimum 6 hours of light requirement should be fulfilled. Since it becomes dormant during winter, it won’t require much sunlight during winter. While growing Triangle cactus as a miniature plant indoors, always place it in the windows receiving at least 4 to 6 hours of daily sunlight. Therefore, South and West facing windows are best suitable.


Triangle cactus is native to Southern Florida and the Lower Rio Grande Valley of Texas in the United States.

Common Names

This plant is known by various common names. The following are some common names of this plant: Triangle cactus, Dildo cactus, Sword Pear, Night-Blooming Cereus, Barbed Wire Cactus etc.

Other Names

Barbwire acanthocereus, Nun-tsutsuy, night-blooming cereus, barbed-wire cactus etc. are the other names for this cactus.

Special Features Of Triangle Cactus

The following are some special feature of this plant:

  •  This plant can reach up to the height of 2-7 m.
  • Like other cacti, they have numerous spines in their stem.
  • They mainly bloom during the night.
  • They require a minimum of 6 hours of sunlight for proper growth and development.
  • They usually bloom in the rainy season.

Growth Rate

This is a fast growing plant. Various researches suggested that this plant can grow up to 2 meters per year.

Plant Characteristics


They have dark green leaves that have three to five angles. The diameter of the stem ranges from 6-8 cm. Each stem possesses about 3-5 ribs and the cluster of spines are present along the outer edge of the ribs. Areoles are present in the stem that are gray in color. The number of spines differ among the types of areoles. Central areolas have one to two spines measuring 4cm in length. Radial areolas have six to eight areoles which are 2.5 cm in length. These young stems are also eaten as vegetables in some parts of the world.


In order to prevent the losses of moisture, the leaves of this plant are modified into sharp pointed structures known as spines.


Triangle Cactus Flower

Triangle cactus has showy flowers. Flowers are generally white with deep red and orange centers. Flowers generally bloom at night but remain closed during the day. Flowers measure about 14-20 cm in diameter. This plant generally flowers for several weeks. Flowers of this plant attract hummingbird moths. Insects are the major pollinators of this plant.


The red colored fruit measures about 5 cm in length. Ovoid oblong fruits are sweet and edible.

Botanical Classification

                    Kingdom: Plantae

                   Clade: Tracheophytes

                   Clade: Angiosperms

                   Clade: Eudicots

                  Order: Caryophyllales

                  Family: Cactaceae

                  Subfamily: Cactoid

                                                                                                  Genus: Acanthocereus

                                                                                                 Species: tetragonus

Is It Toxic?

This plant is not listed as a toxic plant. So, this plant is safer for all living creatures including humans, all pets etc.



It requires bright sunny conditions. Areas receiving bright sunlight are highly suitable for Triangle cactus. This plant cannot grow in shade condition. This plant can also perform well in partial shade conditions. However, a minimum of six hours of daily sunlight is crucial for it.


Temperature between 50-70oF is considered suitable for this cactus. It usually prefers frost free growing conditions. As the Triangle cactus plant is not winter hardy, it is good to plant it in a pot. So, when temperature drops to -1.1oC it can be easily transferred indoors.


Well drained fertile soil is suitable for Triangle cactus. Sandy soil is considered best for Triangle cactus cultivation. Mild acidic, neutral to mild alkaline soil is good for its cultivation. Generally, it performs better in soil of pH 6.0 to 7.5. The potting soil should be composed of pumice, perlite and grit.


Since this is a cactus plant, it requires a moderate quantity of water. Watering should only be practiced when the top 1 inch of soil is dry. Water the plant in such a way that soil is moist but not soggy. Like other cactus plants, it is also fairly drought tolerant. You need to follow the following two rules while watering your plants.

  •  Watering should be practiced directly i.e. it should not be done from the top of the plant. You need to directly water the soil. This helps in retaining the moisture for a longer duration of time.
  •  Always avoid over watering. You have to immediately stop watering when water starts spilling out of the drainage hole.


Like other cacti, this plant also prefers low humid conditions but also survives well in moderate humidity. However, high humidity is detrimental to the growth and development of this plant.


During the growing season, this plant needs to be fertilized with a liquid cactus fertilizer.

Potting and Repotting

Triangle Cactus In Pots

Repotting is required when the plant is outgrown in the pot. To avoid the pot bound condition repotting is required. Before repotting, ensure that the soil must be dry and then gently pull away the plant. Then, soil adhered to the root is knocked away which facilitates the pruning of rotted root that should be pruned away. After pruning the cut side is treated with the suitable fungicide. Then, a new large sized pot is filled with potting mixture and an uprooted plant is planted in it. The plant is kept dry for about a week and then it is watered lightly to avoid the risk of root rot.

Trimming and Pruning

Timely trimming of the cactus plant is required to remove offsets, reinvigorate the plant that has grown too tall and to remove damaged parts. Beside this the trimmed part of the plant can also be used as a new plant. Cactus usually require low maintenance i.e. they can thrive very well even under neglectance. However, this plant also requires pruning to maintain its shape and size. The extent of pruning depends upon your purpose of pruning. The diseased part of the plant needs to be pruned regularly to avoid disease transmission. Also pruning is required for facilitating air circulation.


Triangle Cactus

This is propagated by cutting. For propagation by cutting, simply a branch is cut and is replanted in moist but well-drained soil. Following steps should be followed while propagating this plant by cutting:

· At first cut the healthy branch with the help of sterilized scissors.

· Then place the cuttings in a dry pot for 2-3 days.

· After 2-3 days, these cuttings are planted in the well-drained soil.

· Misting should be practiced every day to keep the soil moist until rooting occurs.

Seed propagation is also practiced. Good quality seed should be used for propagation purposes.

Common Problems

This plant has no serious pests and diseases. The following are the some common pest of Triangle cactus:

· Spider Mite

· Scale insects

· Mealybugs

✍️Spraying neem oil is the best solution to prevent the plant from these pests.

Like other cactus plants, root rotting is a severe disease of this plant. It is mainly due to over watering. Excessive soil moisture should be avoided to control root rotting.

Following are the some physiological disorder of Triangle cactus:-

·Corky Scab

These are the irregular patches with corky brown appearance. Most of the time, these patches are superficial and do not penetrate beyond the epidermis.

This problem is mainly due to inappropriate light and humidity levels. By maintaining appropriate light and humidity levels, this problem can be prevented.


Triangle cactus is excellent for your shelves, worktables and other working locations. In India, the price of Triangle Cactus is about 499.


· The prolific branching habit of Triangle cactus has made it excellent for occupying empty spaces.

· Since it requires low maintenance, it is easy to grow.

· This is an excellent ornamental plant.


· The Vastu and Feng shui experts suggest that this cactus brings bad luck to home.

· The prickly spines may cause pain if they come in contact with our body.


Triangle cactus is basically an evergreen tall columnar cactus. It can measure up to the height of 2-7 m in length. This plant is adapted to tropical climatic conditions and requires bright sunlight for at least 6 hours of day for proper growth and development. You can grow this plant both indoors and outdoors. This plant flowers only during night and flowers are white in color. Since, this plant is non-toxic and hence considered safe for all living creatures. You can propagate this plant either by seed or by cutting but cutting is generally preferred.


  • Sochan Limbu

    A graduate of the Agriculture and Forestry University, Nepal, Mr. Sochan Limbu is an agriculture professional. The author has worked in the gardening field for more than three years and has practical knowledge on how to handle and care for succulents. Get started gardening with his articles.

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