The Beautiful Blue Cacti —Pilosocereus

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! There’s a genus of columnar cacti called Pilosocereus that are so vibrant and blue that you almost won’t believe they’re real. They often have contrasting orange spines too, which makes 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. If you want to learn more about where these amazing cacti came from and how to care for them in your own garden, keep reading!

The Beautiful Blue Cacti—Pilosocereus
The Beautiful Blue Cacti—Pilosocereus @florariym40

Origins of the Pilosocereus

Pilosocereus is a genus of tall columnar cacti that can be 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 come across, 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 really 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 Pilosocereus Cacti

By now 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  for Pilosocereus Cacti

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

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

Before you give 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 soil. 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 check the soil again later. 

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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 the summer months. In Brazil, Pilosocereus grow in full sun in temperatures as high as 125 degrees, so you likely won’t have to worry about sunburn with this cactus like you would with other succulents. 

One thing you do have to worry about when it comes to growing Pilosocereus is frost. In their native environments, they don’t really 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 already fast growers, 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 you apply fertilizer to your growing cactus, make sure you 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, are you going to get one of these amazing 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 really believe this cactus will add a gorgeous pop of color to your garden. We wish knew about them years ago!

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

Looking to add some additional cacti to your garden? Check these cacti out with our articles in The Soft Monkey Tail Cactus, The Rat Tail Cactus: Everything You Need to Know, Everything You Didn’t Know About the Star Cactus, or 9 Rare Cacti That’s Hard to Find!

Loved learning about this cacti and now inspired to add more to your collection?! (We don’t blame you) Check out Succulent City’s new line of 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! 🌵

The Beautiful Blue Cacti —Pilosocereus
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