Myrtillocactus geometrizans (Blue Myrtle Cactus) Plant Care Guide

The Myrtillocactus geometrizans is a member of the family Cactaceae and is native to northern and central Mexico and to Oaxaca where it is abundant in xerophilous scrub and tropical deciduous forests.

Myrtillocactus is from the Greek word myrtillus which means small myrtle, and cactus. Geometrizans, on the other hand, signifies the geometric marking on the plant.

Due to the blue-green color and growth habit, it has several common names including blue candle, blue myrtle cactus, whortleberry cactus, and bilberry cactus.

Size and Growth

A candelabra-like highly branched cactus that can grow up to 14.8 feet or 4.5 meters in height. Its stems are blue-grey in color and are up to 4 inches or 10 cm in diameter.

This plant also has 5 to 8 ribs and areoles, which are about an inch or 2.5 cm apart. Each areole normally has 3 to 5 spines that are up to 0.5 inches or 1.3 cm long.

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The Blue Myrtle Cactus has flowers that are greenish-white in color and are up to 1.4 inches or 3.5 cm in diameter. The flower is fragrant and attracts pollinators.

After flowering, the Blue Myrtle Cactus also produces edible fruits that are dark red in color, oblong and are up to 0.8 inches or 2 cm in diameter.

How to plant a Blue Myrtle Cactus

Using Blue Myrtle Cactus Stem Cuttings

Step 1: Propagate

To use stem cuttings to propagate a Myrtillocactus, simply remove a stem from a well-grown branch of the plant with the use of a sterile knife or a clean pair of scissors.

Step 2: Dry

Let this stem cutting or callous dry completely before potting it into the soil. Drying a stem can take up to three weeks, however, it can be more until you see a white callus forming at the base of this stem cutting.

Step 3: Temperatures

Propagate in warm months of the year, where temperatures are about 65 degrees Fahrenheit or 18 degrees Celsius, in order for the roots to properly develop.

Using Blue Myrtle Cactus Seeds

Step 1: Sourcing seeds

To use seed in propagation, choose a ripe fruit from the plant and clean it. Let it dry completely.

Step 2: Dry

Once fully dried, plant the seeds into the soil.

Step 3: Temperatures

This process should also be done in warm months, during spring or the summer months.

Cactus – Succulents Plant Care Guides

Tips for Cultivation and Propagation

Planting Tips


A Myrtillocactus requires soil with good drainage, preferably a cactus and succulent soil that is mixed with a good amount of gravel. You can put pebbles at the bottom of the pot for good drainage and air circulation. You can also add gravel around the plant to mimic a rocky environment, which is usually home to cacti.


The Myrtillocactus Geometrizans is a fast-growing plant, thus its roots can quickly outgrow the pot, so make sure you repot it once every other year.

When repotting, you need to always check the roots for damage and remove any wilted roots. After repotting, do not water the plant, allow it to adjust for about a week because dry soil will make it easier for them to transition.


The ideal container or pot for Myrtillocactus Geometrizans should be made out of clay. This is because the plant can be very heavy, therefore it needs a pot that is able to support its weight.

Ceramic and Terracotta can also be excellent choices because they are heavier than plastic and they allow water to evaporate from the soil faster and aid with soil aeration.

Blue Candle Cactus Growing Tips


While this is a tough plant, it still won’t be able to handle the cold weather. If you live in a location with cold winters, it is advisable not to grow a Blue Myrtle Cactus outdoors because the frost can kill it.

If you choose to grow this plant indoors, make sure to regulate the temperature and make sure it does not drop under 50 degrees Fahrenheit or 10 degrees Celsius.

The Blue Myrtle Cactus thrives in USDA zones 9 to 11, which are warmer zones located on the southern coastal margins and in the deep southern part of the country.


Young Myrtillocactus Geometrizans require partial shade or filtered sunlight and as they mature, their love for sunlight increases and so it is best if they are fully exposed to the sun.


During the growing season, regular feeding is required. Thus it is best to fertilize it once a month or do it once every three weeks.

Choose a fertilizer with a high concentration of phosphorus and low in nitrogen. During winter, do not fertilize the plant because it will go into its dormant phase.

If the Myrtillocactus is potted, put it in a slightly darker area during the cold winter months for it to hibernate.

Blue Candle Cactus Watering Tips

Climate Conditions

How frequently you should water this plant will depend on the climate conditions where it is grown. The schedule really does not differ from other cacti and that means that a Myrtillocactus should not be watered until the soil is completely dry.


During winter or colder months, reduce the watering frequency. You should only water a Myrtillocactus once every couple of weeks during the winter season to prevent the stems from wrinkling.


Unlike other succulents, the Myrtillocactus cannot thrive in a humid environment, so it is best to avoid misting and try to put the plant in an area where humidity levels do not exceed 30 percent.

Grooming and Maintenance

While a Myrtillocactus is easy to grow, it does not need pruning or too much care. Once planted, you only need to pay attention to sun exposure and watering frequency to make sure it will grow healthy.

Additionally, it needs to be protected from extreme cold weather conditions, in order for it to stay alive.


Myrtillocactus Geometrizans are attractive to butterflies, moths, bees, and birds but are not susceptible to many pests and diseases, however, they can develop root rot if they are damp and poorly drained soil for an extended period of time.


The Myrtillocactus is a popular cactus species for cultivation. It is widely used as a grafting supply for cacti plants, as added decoration to landscapes and its fruits are widely consumed in Mexico, thus it is also grown for commercial purposes.

Frequently Asked Questions

Is Myrtillocactus geometrizans psychoactive?

The plant itself is psychoactive because it contains mescaline, which is one of the strongest substances known to man and has the ability to change a person’s mental state by affecting how the brain and nervous system work.While the fruits are edible and the cactus is generally nontoxic, it can cause gastrointestinal ailments in pets, so make sure to keep the plant out of reach

How fast do Myrtillocactus Geometrizans grow?

A The Myrtillocactus geometrizans cactus growth rate is fairly fast or moderate. It can grow over 3 feet or 90cm in just a few years. On average, a mature plant can grow as tall as 16.5 feet or 5 meters, when grown outdoors. Fortunately, it has a shallow root system, which means you only need to re-pot it once every two years.

How do you identify Myrtillocactus Geometrizans?

bluish-gray stems which are thick and heavily ribbed and forms an architectural structure. Along these stems are areoles with black radial and central spines.When a Myrtillocactus Geometrizans is two years old, it will begin to form greenish-white flowers that eventually turn dark red in color and bear dark red or blue oblong fruits which are edible.

How much water does a Blue Myrtle Cactus need?

A Blue Myrtle Cactus needs 0.8 cups of water every 12 days if it is potted in a 5.0″ pot and does not get direct sunlight. The watering frequency should depend on the climate conditions, additionally, this plant should not be watered when the soil is not completely dry.


Myrtillocactus Geometrizans are candelabra-like plants that are rarely seen indoors, however, with proper care, it can add some liveliness to any garden or landscape. This plant is very tough and sturdy and is probably one of the few plants that need minimal care.

Although their spiky appearance and size make them look bad as houseplants, any person who invests in a Blue Myrtle Cactus will have a supply of bilberries and cuttings. If you do decide to grow one, you should be a responsible caregiver and ensure that the plant is receiving proper treatment.