The Blue Torch Cactus ‘Pilosocereus Pachycladus’

Pilosocereus Pachycladus featured image

Did you know that cacti can be bright blue? Yup, that’s right—those photos you’ve seen on Instagram of blue cacti are not fake nor photoshopped! A genus of columnar cacti called Pilosocereus is so vibrant and blue that you almost won’t believe they’re real. They often have contrasting orange spines, making them look even more beautiful and unreal!

Even though most Pilosocereus cacti have an otherworldly color, they’re not rare or hard to track down. Species like Pilosocereus pachycladus are widely cultivated, so you may even be able to find one at your local garden center!

Like all cacti, Pilosocereus love to soak up the sun and hate the cold. Keep reading if you want to learn more about where these great cacti came from and how to care for them in your garden!

pilosocereus azureus
Pilosocereus azureus @Pinterest

Origins Of Pilosocereus Pachycladus

Pilosocereus is a genus of tall columnar cacti found in warm areas of the world like Mexico, Brazil, and the Caribbean. There are about 50 different species of cacti in this genus, and although not all of them are that vibrant bright blue color we love, many of them are!

Many species of Pilosocereus also have white wool covering them, which is how the whole genus got its name. Pilosocereus roughly translates to “hairy candle” in Latin. It’s probably one of the funniest plant names we’ve ever come across, but it makes sense! These blue cacti have a columnar shape that resembles a candlestick, and they are pretty hairy because of all that white wool! 

Two other things that make these blue cacti unique are their beautifully colored spines and flowers. Many of them have bright orange spines and vibrant blue flowers that match their beautiful blue stems. These are some of the most colorful cacti we’ve ever seen, so they’re a great way to inject a little color into your garden! 

One more thing to note about Pilosocereus is that they can get to be tall. Some species reach 32 feet before they’re done growing! Because of how tall they get, most succulent gardeners plant them outdoors in the ground instead of keeping them in pots inside. They also tend to do better outdoors because they need so much direct sunlight, so that’s something to keep in mind. 

The Beautiful Blue Cacti—Pilosocereus
Bright orange spines @trexplants

How To Care For The ‘Blue Torch Cactus’ Pilosocereus

You’re probably dying to get your hands on one of these bright blue beauties so you can plant the cactus in your garden. But first, you’ll have to learn how to care for it! Keep reading to find out what you need to do to keep the newest addition to your succulent collection happy and healthy.

Water and Soil Requirements

Pilosocereus can handle more water than other succulents and cacti, especially in the summer, but you still have to be careful not to overwater them! Their roots will start to rot if they sit in too much water or soil that doesn’t drain well. That’s why it’s essential to use cactus soil with lots of gritty ingredients. We like this one because it has perlite, sand, and limestone, which all promote drainage and help the ground dry out faster. 

Pilosocereus are pretty thirsty cacti! Some gardeners report that they need water almost daily during the warmer months. We recommend watering your Pilosocereus plant about once a week for most of the year. We then watch it closely in the summer and give the plant more water.

Before giving your cactus a drink, always remember to test the soil first. This helps prevent overwatering and root rot. Stick your finger or a moisture tester in the ground. Do this about once a week during the colder months and once a day when it’s warm outside. If the soil is dry a few inches down, give your cactus some water. If not, wait to water the cactus and recheck the ground later. 

The Beautiful Blue Cacti—Pilosocereus
Pilosocereus are pretty thirsty cacti! @charleen_aiden

Temperature and light requirements for Pilosocereus Cacti

Pilosocereus are from hot countries like Brazil and Mexico, so they love warm weather and full sun! They grow best in tropical temperatures of 70 degrees or higher and need lots and lots of bright, direct sunlight. Don’t be afraid to put them in full sun, even during summer. In Brazil, Pilosocereus grows in full sun in temperatures as high as 125 degrees, so you likely won’t have to worry about sunburn with this cactus-like other succulents. 

One thing you do have to worry about when growing Pilosocereus is frost. In their native environments, they don’t face temperatures lower than 50 degrees. If there’s a cold snap, your cactus may get damaged. So make sure you take measures to protect your cactus by using a frost cloth when the temperature dips. And of course, don’t try to grow a Pilosocereus if you live somewhere that gets lots of snow and ice! 

The Beautiful Blue Cacti—Pilosocereus
Top view of the Pilosocereus cacti @jacquelinetaylor9611

Fertilizer Requirements for Pilosocereus Cacti

Pilosocereus cacti are fast-growing, but fertilizing them can help them grow even faster! They grow fastest in the summer, so that’s the best time to fertilize them. Use a water-soluble, balanced fertilizer, like this one, up to once a month during the summer. 

Before applying fertilizer to your growing cactus, dilute it to half strength so it doesn’t burn your plant. If the package says to use a tablespoon for each gallon of water, use a half tablespoon instead.  

There you have it! Those are our best tips for keeping your Pilosocereus cactus happy and healthy.

Now that you know more about them, will you get one of these great blue cacti Pilosocereus for your garden? Let us know in the comments section below! Happy planting! 

The Beautiful Blue Cacti—Pilosocereus
Blue cacti Pilosocereus @florariym40

We believe this cactus will add a gorgeous pop of color to your garden. We wish we had known about them years ago!

Are you already growing a Pilosocereus (or 2)? Drop a comment below on some care tips you’ve experienced with your cactus! And share your photos in our exclusive Facebook group, Succulent City Plant Lounge!

I loved learning about these cacti and am now inspired to add more to your collection?! (We don’t blame you). Check out Succulent City’s new ebooks covering topics from “All the Types of Succulents for Indoor and Outdoor,” “Different Types of Planters,” and many more helpful in-depth ebooks. Head to this link to view our full line of ebooks and get started with our complimentary guide.

Happy planting!

Succulent City chief editor


Succulent City

Hey everyone! Welcome to Succulent City! We are all about succulents, cacti, and a bit about air plants. Ten years back, in 2013, we began the journey with succulents. It started as a simple hobby, crafting and selling charming succulent-themed pins and decorations. But as time passed, our fascination with these remarkable plants grew, and we gained extensive knowledge about them. Therefore, Succulent City is the blog as you see it is now. Enjoy your visit and happly planting!

14 thoughts on “The Blue Torch Cactus ‘Pilosocereus Pachycladus’

  1. Hello again Richard! 🙂

    First of all, best wishes for 2024! 🥳

    In our previous correspondence on 27 November 2023, you may remember I was about to repot my Blue Columnar Cactus, having previously bought all the necessary equipment. 😜

    Due to a busy schedule, I finally began the procedure earlier this Sunday afternoon… 🧤🤨

    However, after succesfully removing it from its old pot, then getting rid of all the old soil and dirt, I was alarmed by what I discovered… 🧐😯

    As indicated in my 5 enclosed photos, all 7 stems were yellow below the surface, in stark contrast with the normally reassuring shades of green visible above it! 😖

    But as for the roots themselves, that I carefully inspected, they curiously seemed to be in decent condition, a week after the most recent watering (on 5 January 2024)! 🤔

    So immediately after the water therapy you recommended (using filtered water at room temperature), I delicately placed my cactus in a horizontal position on a soft cloth placed over a medium-sized wooden bowl! 🚰🧤

    As I understand, it is sometimes necessary to dry a cactus for 4 to 7 days… ⏱️

    I sincerely hope that my beloved succulent can nevertheless recover from this nasty surprise, so any more of your invaluable advice would be most welcome! 🤞🤔


    Mike Pilkington,
    Lyon, France 🌵🇫🇷

  2. Hello again Richard, ????

    I would like to follow up on our previous conversation dated 16 and 17 August 2023 (see below). ????

    As per your advice (perfectly aligned with my own documentation), I recently subjected my precious 7-headed cactus to a well-known anti-pest treatment using diluted insecticidal soap! ????????

    I mixed 250ml of warm filtered water with about 20ml of so-called black soap (“savon noir” in French), which is actually brown and contains olive oil, hence its dark colour)! ????

    After sunset, I sprayed it 10 times from all 4 directions… then 10 more from above! ✨????

    I repeated the exact same operation the following night… ????

    As indicated in my 3 new enclosed photos taken today (especially photos #1+2), my plant has apparently appreciated this shower, looking much cleaner, with evident traces of continued growth on the 3 taller stems as well as the 2 smaller ones! ????⇡????

    Regarding the 2 problematic culprits, a close-up will reveal a few traces of light green amongst the darker taint, indicating efforts to grow, albeit slowly… ????

    Could that be encouraging? ????

    On another subject, you may also notice 2 areas that I marked with a red square on photo #3… ????

    My daily inspections with a magnifying glass could suggest that the aphids you mentioned (also green by the way) have disappeared… ????????

    Nevertheless, would it be wise for me to continue my soap showers, for example once a week? ????

    Thanks again for any precious advice you may have! ????

    Kind regards,

    Mike Pilkington,
    Lyon, France ????????

    1. Hi Michael,

      It’s great to hear back from you. The first thing you have done right is slightly warm filtered water. I have stated in this new post about the same matter: as I know tap water is not good enough.

      The results look encouraging. I think you can continue to do that every 2 weeks. For the spots, if you don’t find aphids around and the spots are not smushy, there is no need to worry about it.

      In the end, it’s good to see the results!


  3. Hello Richard,

    My name is Mike, and I currently live in the French city of Lyon. ????????

    Having proudly acquired a Blue Columnar Cactus just over a year ago (in July 2022), I recently discovered your interesting Succulent City website! ????

    I was wondering if you might kindly be able to provide a little advice regarding an issue with my plant… ????

    As indicated in my 3 enclosed photos to your email, it contains 7 stems of different sizes, 5 of which appear to be in good health.

    However, 2 of them do not, including:
    – one that is surrounded by the others (with a brown-coloured wound)…
    – another that has a white-coloured mark, does not seem to be growing and has remained dark green (whereas the 5 healthy stems have a combination of light and dark green)…

    A few days ago, I carefully applied a few drops of hydrogen peroxide on the problematic areas (visible in my photo #3), but have yet to see any satisfying results… ????

    Any useful recommandations would be most appreciated! ????

    Best regards,

    Mike Pilkington,
    Lyon, France

    1. Hi Michael,

      Thanks for contacting me! I am excited to receive such requests as yours. I hope the website readers can imagine the plant you described as I don’t know how to embed the pictures here. But I received your email.

      For the first note about the brown spot, I think you gave your cactus too much light. Do you usually put your cactus outside for natural light? You have a pretty cool grow light, so maybe reduce the light a bit to see if things improve. The recommended hours for lighting is about 6-8 hours per day. The other reason for this is fungal disease. However, the high-quality pictures of the cacti you sent me look rather clean and dry. The fungus can only develop in excessive moisture conditions. In this case, there is no use for applying hydrogen peroxide. That’s why there are no changes.

      For the 2nd problem you address, I can’t see the dark green color in your picture. It would be good if you could send another picture of the spot! However, the dark-green thing indicates the lack of light. As I can see from the picture, the cacti grow beautifully but closely together. So, it’s hard to get an even amount of light for each of them (there will be one that gets too much and the other doesn’t). The solution here is to regularly rotate the pot to get light evenly during the sunbathing hours for your cacti 🙂 If you plan on getting your cacti 8 hours of grow light, rotate the pot 3-4 times, 90 degrees each time, without changing the source of light. If it’s natural light, the sun rotates itself so you will need to place it where it gets the full sun. If not, rotate 180 degrees twice will be good.

      I think your question is quite interesting! Can I share this on my website? Also, I hope my suggestions will help.

      I am looking forward to hearing from you soon!

      1. Hello again Richard,

        First of all, thanks for your kind, swift and – most of all – highly detailed response!

        Regarding my research:

        Shortly after I purchased my cactus, I discovered that it actually originates from a remote tropical region in north-eastern Brasil known as Caatinga which is dry… unlike its more famous neighbour, the Amazon… which is obviously wet! The following weblinks lead to an interesting article on the subject ( as well as a fascinating photo of the hostile area itself (!

        Regarding your recommendation for 6 to 8 hours of light per day:

        I was somewhat puzzled, having read that Caatinga, being very close to the Equator, has a daily average of 10 to 14 hours of sunlight… which is precisely what I have been giving my succulent so far, through a combination of natural and artificial light! As I understand, its unique turquoise colour (a mixture of blue and green) provides valuable protection against the very intense sunlight in that part of the world! However, could I have been mistaken? (see my photos #1+2+3)

        Regarding my watering habits:

        I seem to have been reasonable here, as there are no visible signs of root rot! Furthermore, when my local weather is damp, I regularly place my pot (without the saucer) on a piece of kitchen paper that absorbs any humidity at lightning speed!

        Regarding my central stem:

        The brown spot seems to contain a black hole in the middle (see my photo #4) suggesting an infection, even though you advised against treating this… What about using cinnamon?

        Regarding my other problematic stem:

        Whereas the 6 other stems are light green/blue at their tops where they grow (and dark green at the bottom), this one has always been dark green, with one notable exception… bright orange needles on its summit, that curiously disappeared from its neighbours back in May or June… Furthermore, the white mark was made by mealy bugs last year, a nuisance that I was able to eradicate through the use of a pesticide… However, I have been unable to remove it, as I feared damaging the stem! (see my photo #5)!

        Regarding your request to share my original question on your website:

        I would be quite happy to oblige!

        Best regards,

        1. Hi Michael,

          Firstly, thank you for the permission to share this on my website! This case can help other readers a lot. We only have a few confirmed cases like this on the Internet.

          For photos 1+2+3, I think your theory makes sense. However, I still can’t think of a cause other than too much sunlight. If I have to make another suggestion, it would be the initial sign of root rot, which is quite common for the surrounded plant in an arrangement (ventilation & drainage are not that good for such a position). However, as you stated in the watering section and the current weather conditions, there is less likely to be that case. Digging the whole plant up to inspect the root is also not recommended. But digging the whole plant up is the only way if it’s root rot.

          For the brown spot with a hole, have you inspected the plant for pests? As I can see in the picture, if there is a pest, it could be aphids. They are small little pests that can feed on succulents in general, leaving dark sooty molds. If you see aphids around your cactus, access this article for how to get rid of them:

          For photo #5, if the white spots are dry and not so deep, you don’t need to worry about them. Though it affects the outlook of your beautiful cactus arrangements. The darker color tone at the bottom is normal because the bottom of the plant doesn’t usually receive as much light as the top. The orange summit needles seem a bit fried by the sun, in my opinion. Remember to rotate your pot evenly under the light source.

          Once again, I hope my suggestions help!

          Let me know if you need anything else!


  4. Our pilosocereus has been frost burned and we are not sure what to do. If cut down, will it regenerate? The plant has two legs, and there is a small “pup” coming off the bottom of one leg that looks nice and healthy, but the two 6 foot legs are partially browned from a bad frost. We want to save the plant and get t looking healthy again. Please feel free to email me with any advice! Thank you.

  5. Hello! Great article! I have two blue torches and am debating potting them up. Do they grow faster in larger pots? Also, do they have a preference on being potted alone or together? Thank you!

  6. No one can take your article seriously when you use a Copiapoa cinerea that’s photoshopped blue and labeled as pilosocereus.

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Posted in Cacti