Silver Torch Cactus care

The silver torch sactus (Cleistocactus straussii) is a strikingly beautiful columnar cactus. I have a lot of them growing in containers and in my xeriscape. Read more about silver torch cactus care, and ways to encourage faster growth and more flowers.

Before we discuss how to care for Cleistocactus straussii, let’s describe this wonderful cactus!

The columns of this cactus have a lovely, blue-green hue that blends beautifully with its dense carpet of thin, but long white spines. Close-up, you’ll also see thicker and longer spines that are golden yellow emerging from each areole.

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The columns of the silver torch cactus can get about three inches thick, but might reach a height of 10 feet over time.

The great thing about Cleistocactus straussii is that it will develop lots of pups that emerge from its base.

The pups will grow into equally large columns, and then produce their own pups. As each pup grows into a column, it will increase the overall width of the entire plant. That’s why it’s a good idea to give this cactus lots of room from side-to-side.

Over the years, and as this cactus matures, the pups could make the base swell out to a three-foot diameter, or even more. That’s similar to how the organ pipe cactus grows and expands its width.

The flowers on this uniquely striking cactus are a beautiful red color, and it grows into the shape of a long tube. The color and shape of this unique flower is perfect bait to attract hummingbirds.

Like most cacti and succulents, this cactus needs soil that drains well. If you’re planting outside in your landscape, amend clay-based soil with pumice, perlite, and organic garden soil to enhance drainage.

Most cactus varieties love the sun, but the large silver torch cactus plants that I have in a large container only receive a few hours of sun each day. However, it produces lots of flowers, and has not become leggy or unhealthy.

In fact, if you live in the southern United States, this cactus would do well with afternoon shade. And, if you don’t have afternoon shade, this cactus should still do outstanding. A few of my neighbors also have this cactus in full sun, and they look outstanding.

However, if you live in the low-altitudes of the Phoenix, Arizona metro area, it might be best to place this cactus where it receives afternoon shade. In my experience, this cactus is sensitive to extreme afternoon heat and sun, so afternoon shade is best.

The silver torch cactus should be happy outside in USDA hardiness zones of 9-to-11, and it might tolerate temperatures as low as 15 degrees F. However, to be safe, provide some protection by placing coffee cups over the tips if temps drop into the low teens.

In my case, I have never provided winter protection for my silver torch cactus plants here in Phoenix, Arizona. Fortunately, the large ones that I have growing in a large container are very close to my house, so they probably benefit from te ambient heat in the winter.

Just like all cactus plants, the Silver Torch does best when its soil dries out completely before watering again.

Here in the low altitudes of Phoenix, Arizona, I water mine deeply once a week. During that week, the well-draining soil will dry out completely, and then I’ll water!

During the more moderate fall and spring seasons, I water deeply once every two weeks. Then, during the winter, I only water deeply once a month.

Please adapt your water schedule to your specific climate and region. Fortunately, this cactus tolerates a little extra water, as long as the soil is well-draining. But, as always, exercise caution and don’t allow soil to become waterlogged.

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So far, all of my pups from this cactus have emerged from beneath the soil. To propagate those pups, first brush the soil away from the growing pup, and expose the part where it is growing from the main column.

Then, use a knife (preferably serrated), or even a smaller hack saw that is designed to fit into small areas, and cut the pup off beneath the surface.

After a few days, you can move the soil back to cover the wound on the main column. By then, it should have developed a callous.

Then, plant the new pup in a container or in your landscape. Wherever you plant your pup, be sure it has enough space to expand with its own pups.

Here in the southwestern United States, the best time of the year to propagate and replant your cutting is in the fall. That way, your new cactus can develop roots throughout the fall, winter, and spring before it has to face to brutally hot, southwestern summer sun.

In my experience, it’s preferable to replant a cactus cutting (see my photos above) right away. I know many people recommend that you wait until a callous forms, but I do not.

I immediately place the new cactus cutting in its new location. Prior to planting, I make sure that the soil is dry (if the soil is not dry, then I will wait to plant). Then, after a week or so, I water deeply.

By doing it this way, I don’t have to worry about my cactus column lying around outside. In addition, I believe the new cutting can acclimate to its new environment much faster and develop new roots more quickly.

Like all cacti, this variety is easy to grow in your landscape or in a container. I had a large, old container outside next to my garage. To highlight that area and the container, I bought a relatively small Silver Torch Cactus.

Within four or five years, the columns that new planting had grown to over six-feet tall, and developed additional arms that had branched off from beneath its base. As I write this post, this container-based cactus is over a foot wide, with beautifully large columns—it has become a striking focal point at the front of my house!

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TAKEAWAYS:

In summary, the Silver Torch Cactus can be a stunning addition to your landscape, whether you plant it directly in the soil or in a stylish container. This cactus enjoys the sun, is drought-tolerant, and grows fast. You will love it just as much as I do!

Plant in well-draining soil. If you live in a hardiness zone that receives extremely hot summer temperatures, consider placing this cactus in afternoon shade.

I don’t think I’ve ever fertilized this cactus, but you can add a moderate dose of a balanced fertilizer in the spring. Just remember, though, that this cactus can grow extremely fast and get up to 10-feet tall.

After a few years in your landscape, this cactus can quickly grow into a beautiful focal point!

Content and photos by Doug Martin and The Zen Xeriscape