Cleistocactus strausii, the Silver Torch Cactus, is a perennial flowering plant of the cactus family. It is native to the southern regions of Bolivia, growing on mountainous landscapes at high elevations.
This tall cactus is widely distributed in its natural habitat and isn’t under any threat of extinction. Silver Torch’s common name refers to its wooly white or grey spines that cover the entire plant. It is also called the Wooly Torch in some regions.
It is a columnar cactus with long, thin cylindrical stems that can reach up to 10 feet in height but only about 3 inches across. It has about 25 ribs, densely populated with areolas covering the cactus from head to toe.
Wooly, white spines cover every inch, resulting in their distinct appearance. Red flowers emerge horizontally, perpendicular to the stems. The contrasting deep reds of the flowers and the pale white of the stems are startling to behold.
Silver Torch Cactus Main Characteristics
|Common Name||Silver Torch Cactus, Wooly Torch Cactus|
|Botanical Name||Cleistocactus strausii|
|Synonyms||Borzicactus strausii Cephalocereus strausii Cereus strausii Denmoza strausii Pilocereus strausii|
|USDA Hardiness Zones||9a to 11b|
|Mature Size||Height: 3 to 10 feet; Spread: 3 to 6 feet|
|Propagation methods||by seeds, by cuttings|
Silver Torch Cactus Care
As an eye-catching and easy-to-care-for plant, the Silver Torch Cactus is a great option for any garden! With its beautiful flowers and interesting spines, it is sure to add some personality to wherever you choose to put it.
Light and Location
The Silver Torch Cactus grows best in full sun. It can tolerate some partial shade, but it will not flower as well in these conditions. If your region regularly experiences harsh sunlight, it is best to provide some afternoon shade to prevent the plant from getting too much direct sunlight.
Cleistocactus strausii is a drought-tolerant plant but prefers being moderately watered in the growing season. Water the plant deeply but infrequently to allow the roots to develop properly. After watering, make sure the soil is dry before you water again. It is best to water even less during the winter months, as the plant will go dormant during this time.
The Silver Torch Cactus is somewhat of an oddball among cacti since it doesn’t appreciate hot weather as much as others in its family. In fact, it prefers much cooler temperatures, around 40 to 50 degrees Fahrenheit. However, if kept dry, it is tolerant to temperatures well below freezing, going as low as 14 degrees Fahrenheit without issue. Don’t treat this one like regular cacti as its temperature needs are slightly different.
Cleistocactus strausii prefer dry conditions. Like other cacti, they cannot tolerate being in a moist atmosphere for long periods. Average room conditions are usually sufficient; no special measures need to be taken.
Cleistocactus strausii likes to be fertilized in the growing season. So fertilize using low nitrogen fertilizer twice a month from early spring to the end of summer. Just make sure to use diluted feed.
The Silver Torch Cactus produces beautiful, bright-red flowers that bloom in the summer. They will only bloom if they receive enough time under direct sunlight. The flowers are tube-shaped and grow from the sides of the stems. These flowers never open all the way; only the stamens and the outside of the petals are visible.
Cleistocactus strausii can be propagated by both seeds and cuttings.
If you choose to propagate by seed
- Plant the seeds in a cactus mix or well-draining potting soil.
- Water the soil until it is slightly damp, and place the pot in a warm location with bright, indirect light.
- The seeds should germinate after a few weeks.
- Once the seedlings have grown to a sufficient height, you can transplant them into their own pots.
By Stem Cuttings
To propagate by cuttings:
- Take a cutting from a branching stem of the main plant in the spring or summer.
- Wait for the cutting to callus over for a week or two before planting it in a cactus mix or well-draining potting soil.
- Provide moist conditions and place the pot in a warm location with bright, indirect light. The cutting will take root in four to eight weeks.
- Once it has rooted, it can be transplanted into its own pot.
(Note that stem cuttings need to be taken from the base of the plant, and it affects the aesthetics of the plant significantly. Unless your main stem has enough to spare, this isn’t recommended. Therefore, propagation by seeds is standard. As these cacti flower quickly in cultivation, getting your hands on a few seeds isn’t hard.)
Potting and Repotting Silver Torch Cactus
The Silver Torch Cactus can be grown in either a pot or planted in the ground. If you choose to grow your plant in a pot, it will need to be repotted every few years or when the roots become cramped. When repotting, use a cactus mix or well-draining potting soil and a pot that is only slightly larger than the current one. Water the plant deeply after repotting, and then allow the soil to dry out completely before watering again. Use a standard cactus mix as the potting medium for the best results.
Cleistocactus strausii is not toxic to humans or animals.
The Silver Torch Cactus is a hardy plant that is not susceptible to many pests. However, it can be infested by mealybugs on occasion. Mealybugs are small, white insects that feed on the sap of plants. They can cause stunted growth and stress to the plant. To get rid of them, wash them off with a stream of water or use a standard pesticide.
How To Grow A Silver Torch Cactus – Care Instructions and Tips (Video)
How To Water Silver Torch Cactus?
The Silver Torch Cactus likes to be watered deeply, but only when the soil is completely dry. Water the plant thoroughly, and then allow the soil to dry out completely before watering again. In the winter, you can reduce watering sessions to once a month.
How To Care For Silver Torch Cactus?
Cleistocactus strausii prefers bright sun, well-drained soils, and cool temperatures. Water the plant deeply, but only when the soil is completely dry. Fertilize the plant with a low nitrogen fertilizer twice a month in the growing season.
“File:Cleistocactus strausii 4zz.jpg” by Photo by David J. Stang is marked with CC BY-SA 4.0.
“File:Longwood 2011 09 02 0403 (6160336655).jpg” by Harvey Barrison from Massapequa, NY, USA is marked with CC BY-SA 2.0.