Wherever it is placed, the Blue Torch Cactus always stands out with its columnar form and unusual azure color. Such color saturation is so rare in the plant world!

This plant belongs to the genus Pilosocereus in the Cactaceae family, originating from the subtropical regions of Brazil, Mexico, and the Caribbean. In this article, you will find out its main characteristics, and how to take care of it.

Where Does the Blue Torch Cactus’ Name Come From?

The name of the genus, Pilosocereus, is a combination of the Latin and Greek words meaning “hairy” and “pillar”, describing its gorgeous appearance. The genus includes about 50 species of cacti, many of which have a bluish body. However, only this cactus has a vivid azure blue color, which is why it is called Pilosocereus azureus. In addition to its botanical name, the plant is also known: blue candle cactus, torch cactus, and Brazilian cactus.

What is Blue Torch Cactus

The blue candle cactus is a succulent perennial whose stems have thickened so much in the process of evolution that they turned into a tick, upright, elongated, candle-like trunk. Each trunk has pronounced lobes, with downy fur and golden to orange short spines along its edges.

In nature, this long-lived plant can grow up to 30 feet, but indoor specimens are much smaller and usually do not exceed 12 feet even after a few decades. The almost unreal blueness of this plant intensifies with age if the plant grows in suitable conditions, primarily if it receives sufficient direct sunlight.

And, as if the gorgeous azure color is not enough, when it reaches 12 inches in height, the plant blooms with bluish-white flowers with pronounced pistils and yellow anthers. The flowers open at night and, unfortunately, last only one day. If some of the nocturnal insects pollinate the flowers, the plant will produce Blue Torch Cacti seeds.

Blue Torch Cactus Care

Despite its unusual color, Blue Torch Cactus is a widely cultivated species that you can find in almost every cactus store. The reason for its popularity and availability is simple: it is easy to grow, it is very durable, and does not require any special conditions. Even children can nurture it, provided they avoid its not-so-harmless thorns.

– Soil Requirements

In their natural surroundings, these plants thrive on the barren and roughly textured ground through which water flows quickly. Therefore, Blue Torch Cactus grows best in gravelly soil whose main characteristic is high permeability. On the contrary, soil that retains moisture endangers its poorly developed root system, accustomed to a dry environment.

Ready-made, sand-based mixtures for succulents and cacti, available in almost every well-equipped garden center, are ideal for growing this plant. Another acceptable option is a homemade mix consisting of equal parts of all-purpose soil for potted plants, pumice or perlite, and sand or gravel. Water and air circulate with no difficulties through this combined soil, allowing your Blue Torch Cactus to feel at home.

– Water Requirements

Cacti are generally known as plants that can survive for a long time without water or with minimal amounts of water. The thickened stems that make up the cacti body store the water reserves that the plant uses in dry periods.

However, this is not to say that the plant should not be watered regularly. The plant can indeed survive for weeks even when you do not water it, but it unquestionably grows and thrives much better if you provide it with a proper intake of this vital liquid.

So, do not test its durability for no reason by leaving it endlessly dry! Water it once a week from spring to autumn and once a month in the winter. Blue candle cactus, like other cacti, can grow in small pots with a diameter of two to three inches, so seven days is enough for the substrate in the container to dry completely.

If the planting pot is larger, extend the interval between two waterings to ten days. The essence is to water the plant only when the substrate is dry. The cactus will not mind if you sometimes forget to water it, but still, make sure that this azure-colored beauty gets its serving of hydration!

– Light Requirements

Blazing sun — which causes burns on leaves in other plants — is a condition that this sun addict will like! Moreover, the more direct sunlight it gets, the more intense its incredible color becomes.

If you have a south window widely open to the sun’s rays, where other plants cannot survive, then you have found a perfect place where your Blue Torch Cactus will enjoy! And not only that! Its spikes turn golden orange if the plant gets at least eight hours of direct sunlight daily, strikingly contrasting the blue cactus body.

If you do not have a south window, place your indoor blue cactus on the brightest point in the house while still taking care of it to get at least 6 hours of direct lighting per day. Lack of light will not endanger the life of this plant but, in such circumstances, the plant will not be nearly as beautiful as those that grow exposed to adequate lighting.

First of all, the azure color of the body may completely vanish. The plant will elongate and bend towards the light source, losing its shape. And, of course, in such an environment, you can forget about flowering, regardless of your plant size and age.

– How To Provide Enough Sunlight

If you do not have a position in the house that allows the plant to absorb enough light during the growth phase, take it outside on a sunny balcony or in the yard as soon as the dangers of late frosts pass. In doing so, take care to gradually give the plant time to get used to the new conditions!

In other words, do not immediately expose it to the bright sun from the shadowed room for the whole day because the plant will not have enough time to adapt to such a shocking change. For the first few days, two or three hours of direct sunlight are more than enough. Later, when the plant hardens, you can leave it to sunbathe and enjoy the sun all day long.

– Temperature Requirements

Cacti are rightly associated with hot, dry climates because these plants do not like moisture or low temperatures. If you live in the northern hemisphere, you need to protect your Blue Torch Cactus in winter since it is not resistant to frost, and it can decay at a temperature below 30 °F. The water in its stems turns into ice crystals, which tear down the cell structure and destroy the plant as soon as the temperature approaches the freezing point.

Therefore, you need to bring your plant into the house at the end of September in case winters tend to be rigid in your area. The optimum temperature for its cultivation ranges from a minimum of 65 to a maximum of 90 °F. At temperatures below 60 °F, the plant enters the dormant phase when its needs for water or nutrition are even less than usual.

Outside of controlled home conditions, you can grow the plant outdoors, in the garden, only if you live in the United States climate zones 9b to 11. In such regions, the plant can spend the winter outside, but it would still be good to protect it in the colder months with a burlap cover or frost blanket. This protection will prevent freezing and root rot caused by increased soil moisture in the wet winter months.

– Fertilizer

Blue torch cactus has developed the ability to grow in sparse soil without an abundance of nutrients. In other words, it is not a “spoiled” plant that needs constant replenishment or fertilization to grow.

Once you plant it in a mixture to which you have added a little compost or vermicast, there is no need to fertilize it further. Moreover, excessive nutrient intake can damage the root and cause more problems than benefits.

If you do not have organic fertilizer on hand, you can use slow-release fertilizers intended for cacti. Their chemical composition is adapted to the needs of succulent plants. You can apply it in spring and thus provide even feeding until the end of the season since this product gradually decomposes.

Best of all, the plant will grow without any additional fertilization as long as other conditions are within optimum limits. Fertilizing is, therefore, an option that you can — but do not have to — consider when growing this plant.

– Humidity

Although marked as a semi-succulent that grows in areas where the percentage of air humidity ranges from 40 to 70 percent, this cactus tolerates dry, almost desert conditions. It means that it has a high degree of adaptation to air moisture, and it thrives just as well in dry as in slightly wetter conditions.

All in all, the humidity of the space is not something you have to worry about. Like any succulent, it will be bothered by extreme wetness. But, fortunately, the average home environment is far from the values that would damage this plant. Blue Torch Cactus generally feels quite good in standard indoor conditions.

– Potting and Repotting

The roots of the blue candle cactus spread vertically just below the surface of the substrate. It is the consequence of the long-term adaptation to very hard, often stony or rocky soil in its homeland, through which the root cannot penetrate.

Therefore, when planting candle cactus, choose broad and shallow pots that allow the root ball to spread and establish the stability of the raised columnar body of the cactus. Of course, the container must have drainage openings through which excess water will drain from the substrate.

Also, pots made of natural materials such as clay or terracotta are more suitable for growing cacti than plastic ones because they absorb moisture from the soil and prevent water accumulation around the plant’s roots.

As the plant is not accustomed to its roots having a lot of space, it can grow for years in the same pot because it does not mind root bounding. However, every second or third year, replace the worn substrate with a fresh one. You can replace the pot with a slightly larger one only when the roots fill the previous pot. And of course, when transplanting, be sure to wear protective gloves and wrap the plant in a newspaper or an old cloth to avoid the unpleasant stings of its thorns.

Propagation

Blue candle cactus usually grows as a single trunk adorned with side offsets like many other cacti. Therefore, if you want to propagate your indoor blue cactus, you can do so in two ways: by top cuttings and seeds.

– Top Cuttings Propagation

If you have an adult specimen that has grown at least 8 inches, you can multiply it by cutting off its top to a length of at least one inch.

  1. Leave the part in the shade for seven to 15 days to dry, harden, and form a scab. The lower section around the incision will shrink because the plant is trying to heal the wound, drawing water from that part, which should not worry you.
  2. When the wound heals, insert the cutting into the prepared container with the substrate. The healthy, fresh part of the cutting should be above the surface or level with it.
  3. Press the soil around the cactus with your fingers to ensure its stability, but do not water it for at least the next few days.
  4. Five or six days later, water the plant by pouring water along the edge of the pot.
  5. If the rooting process is completed, the plant will provide resistance when you move it, indicating that the root is anchored to the ground.

Further, nurture it like an adult plant.

– Seed Propagation

Propagation from seed is possible, but it can be a lengthy process that requires a lot of patience.

  1. Prepare a container filled with the cactus mixture soil.
  2. Moisten the substrate using a sprayer.
  3. Scatter the seeds on the surface. The seeds do not have to be evenly distributed because they germinate even better if they are clustered.
  4. You should not cover the seeds with soil as they needs light for germination.
  5. Cover the pot with a plastic bag on which you drilled a few holes for air circulation.
  6. Put the pot in a bright and warm place, because the seeds germinate at temperatures above 65 °F.
  7. Occasionally mist the surface to maintain moisture. Sprouts can appear in a few weeks, but also a few months! Therefore, don’t give up right away.

Once small new cacti appear and grow one inch in height, you can transplant them into individual pots.

Common Problems of Blue Torch Cactus

The essence of caring for cacti is not to care too much about them. They are an example of superior adaptation, capable of surviving even when left to themselves. You will endanger them only if you water them more than they need. Sitting in a moist substrate is basically their only weak point.

Moisture in the soil will cause the roots to rot, causing the disorder to be transferred to the trunk. This process is not always immediately visible because it starts inside the cactus’ body. When the external signs appear, including discoloration and mushy tissue, it is usually too late!

– Pests

Mealybugs, spider mites, and scales can attack your Blue Torch Cactus, like any other plant in the house. Due to the shape in which this plant grows, their presence will be easier to detect than in deciduous and branched plants. Therefore, you could apply some effective treatments to combat the pests as soon as you notice whitish spots or discoloration.

You can immerse the body of the cactus briefly in a bowl of water until you get rid of the invaders. After the treatment, dry the plant and return it to its place. Neem oil mixed with water and applied by spraying will also help drive away these invaders. Also, a homemade remedy of one part alcohol and four parts water with a few drops of liquid soap will do the job!

Conclusion

Even if you are not a fan of cacti, you will hardly resist this gorgeous species! The proverbially durable and adaptable Blue Torch Cactus can find a place in any home. It is ideal for beginners and those with the will but not enough time to take care of plants. To successfully grow this unreal blue succulent, it is enough to follow the listed tips:

  • Grow it in a very sunny place! More sun means more intense blue
  • Protect it from low temperatures because it is not frost-tolerant, and it needs to spend winter in a heated area.
  • Water it only when the substrate is completely dry!
  • Grow it in well-drained, light soil for cacti and succulents, or prepare a home-made mixture of the same parts soil, perlite and
  • Fertilize it optionally since it will thrive even without additional feeding!
  • Transplant it into a fresh substrate after two or three years, best in spring!
  • Wear protective gloves when handling it! Although short, its spines can still hurt you!

Are you ready to try your hand at growing a Blue Torch Cactus?

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