Blue Torch Cactus
Plant Care,  Succulents and Cacti

Blue Torch Cactus

Welcome to our guide on how to care for and propagate the Blue Torch Cactus…

Blue Torch Cactus Care Summary

Light needs:Bright indirect sunlight ,and some direct.
Watering needs:Check soil weekly and only water if totally dry.
Fertilizer:A dedicated cactus and succulent feed every few weeks in the spring and summer.
Soil:Cactus and succulent mix.
Humidity:40% or less.
Temperature:21-27°C (70-80°F)
Where to buy:Try our list of Rare Plant Shops or Etsy.
Other names:Tree cactus, Pilosocereus Azureus.
Common issues:Overwatering.


Blue Torch Cactus is a rare, stunning cactus with a deep blue trunk, white flowers, and golden spikes. It can grow up to 30 feet tall (9 meters) in the wild and it looks phenomenal both as an indoor as well as an outdoor plant. Since it is native to the harsh conditions of Brazil, Mexico, and the Caribbean, it does not require much maintenance, just don’t overwater it!

See also: Succulent Soil, Coral Cactus, Cactus From Seed, Bear Paw Cactus, Propagation of Snake Plants.

Tip: we recommend Etsy for buying plants. Look for the best rated seller you can, and try to buy as close to your home as possible so the plant does not travel too far.

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Light Needs

It is a sun-loving plant and needs at least 8 hours of direct sunlight every day to maintain its striking blue color. If you are growing it indoors, make sure you place it near a South or West-facing window for optimal sun exposure.

How Often to Water

Check the soil each week and only water it if totally dry. Make sure the pot is not sat in water in it’s saucer or external container, so pour out any excess water once you’ve finished watering. They must not be overwatered, as it can lead to root rot easily, which can be lethal for the plant.


You can use a dedicated cactus and succulent feed every few weeks in the spring and summer. If you don’t fertilize the plant it will be fine, but may not grow as quickly compared to if you do.


You want to use a coarse, well-draining cactus soil, as the roots can rot easily if let to sit in soggy soil. You can use a commercial cactus potting mix or make your own by mixing one part sand, one part compost, and two-part perlite or pumice. See our guide to succulent soil for more.

When To Repot

The plant can grow in the same pot for years without repotting. But I would check them around about Easter time to make sure the roots have room to grow as the weather gets warmer. You can replace the soil every two or three years and change the pot when you see the roots outgrowing the current one.


As long as the environment is not too wet, blue torch cactus grows fine. Do not mist these! They are fine with 40% humidity.


A good daytime range to aim for is 21-27°C (70-80°F), but if it gets down to 10°C or so it will be fine.

How To Propagate

Blue torch cactus propagation is done either by seeds or by top cuttings. Top cutting is what it sounss like: you cut the top part of the cactus and allow it to callus for a few days. Then place it in soil to root.

You can also germinate seeds by planting them in soil and transplanting it to other pots when it gets at least a few inches in size. This can take a long time as growth is slow!

See also: Succulent Propagation (with pictures).

Blue Torch Cactus USDA Zone

Zones 9-11.

Other Names

Tree cactus, Pilosocereus Azureus

For more on succulents and cacti, see our succulents category with all our care guides.

Where To Buy

Try our list of Rare Plant Shops. Or Etsy.

FAQs and Common Problems

Apart from a few common issues such as pest infestation and overwatering, it does not face any serious problems. Observe your plant weekly at watering time.

How Do I Make My Blue Torch Cactus Blue?

Give it a much light as you can to keep it healthy.

Why Is My Blue Torch Cactus Turning Green?

A blue torch cactus can trun green if not given enough light.

Is Blue Torch Cactus Psychedelic?

Yes, it contains mescaline. Do not eat these without seeking advice first!

How Fast Do Blue Torch Cactus Grow?

They can grow up to 50 cm a year (one and a half feet).

Are Blue Torch Cactus Poisonous?

The blue torch cactus itself is not poisonous; however, it has some pretty sharp spines on its trunk. The spines are not toxic, but they can injure and cut the skin if touched without proper care.

How Big Will The Blue Torch Cactus Get?

They can grow up to 30 feet tall, yes really!

Does Blue Torch Cactus Flower?

It has large white flowers with a yellow interior that blooms at night.

Other Articles You Might Like

Hope you liked our article, you might also like these articles: Succulent Soil, Coral Cactus, Cactus From Seed, Propagation of Snake Plants.

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