Fairy Castle Cactus Plant Care

Here we have another night-blooming cactus known as the fairy castle cactus. When you look at the cactus, it grows turrets similar to a castle. It is a columnar cactus, low maintenance, and easy to care for.

So, if you have one or not, we have all the info on taking care of the fairy castle.

More About the Fairy Castle Cactus

fairy castle cactus

The fancy name in botanical terms for the fairy castle is Acanthocereus testragonus, native to Mexico, Southern United States, and Central America. Yet, the plant does look like a medieval castle as it grows.

Another exciting thing is that many referred to it in the past as Cereus tetragonus. Yet, the debate is continuing on how it should be classified. Many scientists say it is a cultivar of the Cereus hildmannianus, and others say it comes from Cereus hildmannianus F. monstruorus.

But no matter the fancy name, it remains a favorite cactus to grow that is easy to care for. You can grow it as an indoor plant or in a garden. It is a slow-growing plant also with another common name, barbed wire cactus.

While it rarely blooms, it can become a showy plant with large white or yellow flowers.

Fairy Castle Cactus Care

fairy castle cactus care card

The fairy castle cactus is a very low-maintenance succulent and slow grower made for beginner plant parents.

The Type of Soil That Fairy Castle Cactus Needs

The fairy castle cacti need the same soil as most other plants in the cacti family. Hence, an important part is to provide drainage holes with soil consisting of sand, pumice, gravel, bark, or perlite.

We do not recommend using water retention potting mediums like an unglazed clay pot or peat moss. You can also use a cactus or succulent plant mix. Whether grown indoors or outside, drainage remains essential.

You can grow your fairy castle in a raised bed or berm, while enough drainage holes are essential in containers. It allows excess moisture to flow from the pot for you to remove. Removing the excess water is necessary to prevent root rot.

Light Needs for Fairy Castle Cactus

fairy castle cactus lighting requirement

The fairy castle cactus thrives in a lot of light, similar to other succulents. As long as it has well-draining soil indoors or outdoors, it can survive in full sun to partial shade. Still, when you bring your plant home from the garden center, it helps to slowly introduce it as a full-sun plant over a few weeks.

Doing this prevents sunburn on the foliage and is irreversible. The same applies when growing fairy castle cactus indoors; it grows best in direct light. If you cannot provide your cacti plants with enough sun, it helps to invest in growing lights.

Signs that your night-blooming cereus is not receiving enough light are yellow stems and branches. Furthermore, the top growth will appear thinner.

How To Water Fairy Castle Cactus Plants

As the cactus plant is such a slow grower and a succulent plant, it does not need a lot of water. In addition, it helps to let the soil dry between watering to prevent overwatering. A common sign your plant is overwatered is that it might look plump at first with new growth.

Yet, growth comes at a price as everything that can go wrong is happening underneath the soil. The rot eventually moves up the stem, and you notice mushy, blackened branches and stems.

You may need to water frequently in summer as the water evaporates fast. During winter, your barbed wire cactus grows slowly and requires less water.

Fertilizer Needs

plant fertilizer

In the growing season, you can provide some plant food to the soil or in water for your fairy castle cactus. Refrain from feeding fertilizer in winter as your plant is dormant. You can choose a soluble feed rich in nitrogen and phosphorous to develop healthy spines, blooms, and stronger root growth.

Temperature and Humidity Levels

Your fairy castle grown indoors can become sensitive to cold drafts and is not frost tolerant. When grown outdoors, it is best to bring your plant inside as it is not cold hardy. So, if temperatures dip below 30°F, keep your plant indoors until the weather warms up.

Neither does it need high humidity and prefers low to medium moisture in the air.

Repotting and Propagation

When repotting your fairy castle cactus, you can use an unglazed clay pot, but it needs to have enough drainage and soil made up of coarse sand or cactus potting soil. You can also propagate your plant using the fairy castle cactus cutting or seeds.

From seeds

You can collect the seeds from the fairy castle fruit, but it rarely blooms. Or you can buy the seeds online and need patience with well-draining soil kept moist but not wet until seedlings sprout. During the first growth cycle, planting fairy castle cactus will grow a few inches but takes patience to produce spires.

propagate from cuttings

A standard method is to use cuttings as your fairy castle cactus produces branches, and collecting cuttings is simple by breaking them off. For example, you can follow these simple steps:

  1. Use a sterile sharp knife or scissors with protective gloves to collect cuttings.

  2. Leave the cuttings to be callous for a few days to prevent bacterial and fungal infections.

  3. You can dip the cut end into the rooting hormone, but it is optional. As the rooting hormone is a powder, you can dip the cut end into the water before you dip it into the hormone.

  4. Then plant the stem cuttings in well-drained soil that are moist if you use rooting hormone and do not water in the first few weeks.

You can expect a growth of ten inches during the first year and might notice some turrets forming.

Fairy Castle Cactus Varieties

The fairy castle cactus is not the only spectacular cacti plant you can find. Here are some of our favorites for you to browse through.

  • Fairy Castle Variegatus

The slow-growing succulent is a dwarf variety producing many spines with five-sided branches that clump vertically. The plant family grows up to six feet tall with a green to yellow variegation.

  • Triangle Cactus

The columnar cactus has dark green stems with up to four angles. The plant can grow up to 23 feet tall with central and radial spines. The cacti produce flowers and fruits as it matures.

Common Problems With Fairy Castle Cactus

One of the biggest concerns is overwatering your succulent plant. Hence, it is crucial to let the soil dry between watering. Furthermore, it is a hardy plant but can become the home to disease and pests. Here are some concerns you can face with your cactus.


The mealybugs usually attack the body, spines, and roots. The insect hides in narrow spots and looks like white wool over the plant. You can spray rubbing alcohol or isopropyl alcohol over them and check the soil.

Spider Mites and Fungus Gnats

Both these insects can become an issue but are not standard on a cactus. When brought indoors, you must first check your plant outside to prevent it from spreading inside to other plants. Using a mixture of neem oil or insecticidal soap helps.

Root Rot

Rotting of roots happens with overwatering, and your plant turns yellow, brown, to black. You may find it happening from fungus bacteria as well. The best in most cases, when your plant turns yellow, is to check if the soil is soggy and replant your cactus.

For more severe cases, check out our detailed article on How to Treat Black Spots on Cactus.

Where can you Buy Fairy Castle Cactus?

The great news is that the fairy castle cactus is not a rare plant. You can find one at your local garden center or with us at Plantly.

Whether you want to buy, sell or simply reach out to other plant enthusiasts, Plantly is the right place to be!

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