Pilosocereus azureus: Care and Propagation Guide

Pilosocereus azureus has various scientific names like Pilosocereus pachycladus, Pilosocereus atroflavispinus and Pilosocereus superbus, but it is commonly known as blue torch cactus. It is one of the most distinctive columnar cacti.

It can reach a height of 10 feet. Once it grows tall, it starts growing branches at the base. The branches are a vivid blue-green. The stem has ridges and is covered with areoles at the edges.

The areoles have numerous yellowish spines growing out of them, which turn white as the plant matures. It grows white, funnel-shaped flowers.

pilosocereus azureus

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How To Care for Pilosocereus azureus

There are several care requirements that you should be aware of when it comes to growing this cactus at home. Take a look at these below.


You should provide plenty of sunlight to the Pilosocereus azureus to allow it to grow to its fullest extent. On a daily basis, you should keep this cactus under direct sunlight for up to 12 hours.

This can be easier to achieve if you are growing it outdoors, but you can simply place the potted cactus on a suitable windowsill of your house if you want to grow it indoors.

These cacti commonly grow in USDA hardiness zones of 9b to 11b. This means that they can withstand hot and tropical climates but will not be able to do too well in extreme cold. Make sure you bring them in indoors if it gets too cold in winter where you live.


Thai cactus needs a good amount of water to grow healthily. Watering it thoroughly once a week should be sufficient for it. However, you should let the soil become dry enough before you water it again.

Overwatering this cactus can cause root rot which can adversely affect the healthy growth of this cactus. You should water the Pilosocereus azureus regularly during its growing season, which is usually spring and summer.

You do not need to water this cactus in winter since it becomes dormant during this time. However, you can water it once or twice in the season if you think it needs it.


You should grow this cactus in well-draining soil so that any excess water can drain away or evaporate without being retained in the soil. Generally, a good potting soil or cactus mix will work well for this cactus.

You can also add some sand or perlite to keep the soil dry enough.

pilosocereus azureus


Pilosocereus azureus generally does not require too much fertilizer since it can grow well without it. However, you can choose to add a well-balanced fertilizer that contains equal parts of all nutrients. Make sure that you dilute this a bit as it can be a bit too strong for the cactus on its own.

Fertilizing the soil once or twice during the growing season will be sufficient for this cactus. You can also make use of compost for a more organic approach.

Pests and Diseases

Some common pests and diseases that this cactus tends to experience include mealybugs throughout its length, scales and mites, among others. Too much watering can also lead to root rot. Bruises and yellow specks are also common.

If you notice these pests and diseases, you can try to get rid of them using a pesticide or by using rubbing alcohol. You can also simply try to hose them out. It is important to keep an eye on your cactus as these methods will not be as effective if these pests have spread too much.

pilosocereus azureus

How to Propagate Pilosocereus azureus

You can propagate Pilosocereus azureus at home mainly by using cuttings. While you can also use seeds, this can be a much slower process as this cactus may not easily bloom by itself if grown at home.

You can go through the following steps to learn how to propagate the Pilosocereus azureus using cuttings.

  • You should obtain some cuttings from a mature or adult cactus. Once this cactus becomes tall enough, you can cut off some branches from the top of the plant.
  • Make sure you divide the cuttings into small pieces so that you can easily plant them in.
  • Take a well-draining container or pot and place some of the soil mix in it.
  • Plant the cuttings into this soil. Make sure you push them in well and cover them up with enough soil mix.
  • You can then moisten the soil up a bit so that the cuttings can start developing roots.
  • After the roots develop well enough, the cactus will start growing well as long as you provide the required conditions. It will also start flowering well regularly in the growing seasons.