The pencil cactus plant (Euphorbia tirucalli) is native to southern Africa and India. It is also known as the milk bush, pencil tree or firestick. The plant typically grows to a height of 10 feet (3 meters) but can reach up to 20 feet (6 meters) in its natural habitat. The pencil cactus gets its common name from its thin, pencil-like stems covered in small spines. When grown indoors, this plant can grow up to 6 feet (1.8 meters).

The pencil cactus is a succulent plant, meaning that it stores water in its stems. This allows the plant to survive in arid conditions where other plants would quickly perish. The pencil cactus is also known for its ability to tolerate neglect. This plant can go for long periods without water and remain healthy.

Now interestingly enough, the pencil cactus is not a true cactus. It is actually a member of the Euphorbia family, whereas cacti are members of the Cactaceae family. 

Despite its tough exterior, the pencil cactus is a delicate plant. The stems are easily damaged and can even snap off if they are bent too far. It is important to handle this plant with care to avoid damaging it.

If you are looking for a low-maintenance plant that is interesting and visually appealing, the pencil cactus is a great choice. 

Let’s look at some tips for pencil cactus care indoors. 

Light 

The pencil cactus requires a lot of light to flourish. Make sure to place it in a location that receives plenty of sunlight, such as your window that gets the most sun exposure.

If you don’t have enough light in your home or don’t have a well-lit spot, use grow lights to supplement the sun’s rays. If you opt for grow lights, leave them on for about 12-14 hours each day.

Water 

The pencil cactus is a succulent plant. As previously mentioned, this means that it stores water in its stems. Consequently, the plant does not need to be watered very often. So, only water it when the soil is completely dry. Over-watering can lead to root rot, so be careful not to water too often.

Fertilizer 

The pencil cactus does not need to be fertilized very often. Once every two months during the growing season should be sufficient. Just be sure to use a light fertilizer so you don’t burn the roots of the plant.

Soil

The pencil cactus does best in well-draining soil. You can either purchase a succulent potting mix or make your own by mixing equal parts sand and cactus potting mix.

Temperature 

Regular indoor temperatures should be fine for the pencil cactus. Just make sure that the temperature does not drop below 50 °F (10 °C).

Humidity

The pencil cactus does not require high humidity levels. This plant is quite tolerant of dry conditions.

Toxicity

The pencil cactus is toxic to both humans and animals. The sap of the plant contains latex, which can cause skin irritation. If ingested, the plant can cause digestive upset. So, keep this plant out of reach of children and pets.

Propagation

The pencil cactus can be propagated from stem cuttings. To do this, simply cut a stem from the plant and allow it to callous over for a few days. Once the cuttings have dried out, you can then plant them in some well-draining soil. Then place the cuttings in indirect light for about 4 to 6 weeks, at which time the roots should develop.  Once the roots develop, the plant will be able to start growing on its own. Put them in an area that gets indirect sunlight until they adjust to their new environment.

It’s a good idea to wear gloves and protective eyewear when handling the pencil cactus, as skin and eye irritation can develop, if there’s direct contact with the plant’s sap.

Repotting

The pencil cactus does not need to be repotted very often. You can repot the plant every two years or so. Just be sure to use a pot that is only slightly larger than the current one. This will help to prevent root rot.

It’s a good idea to grow this plant in a clay pot enabling extra moisture to evaporate. Additionally, drainage holes are vital.

This video highlights some of the do’s and don’ts of pencil cactus care.

FAQs

Why is this plant called a cactus when it isn’t one?

The plant is called a cactus because of its similarities in appearance to true cacti. Both plants have succulent-like leaves and stems, and both are native to warm, dry climates. However, that’s where the similarities end. True cacti are members of the Cactaceae family, while the pencil cactus is a member of the Euphorbia family.

Why is my pencil cactus droopy?

If your pencil cactus is droopy, it may be because it is getting too much water. The plant will become mushy and some parts of it will fall off. Check the soil and allow it to dry out completely before watering again. Change your potting mix if necessary to one that is well-draining if this problem persists.

How can I tell if my pencil cactus is underwatered?

If your pencil cactus is underwatered, the plant will start to wrinkle and the stems will start to shrivel. The plant may also become discolored. 

Can you touch a pencil cactus with your bare hands?

It is best not touch a pencil cactus with your bare hands. The sap of the plant can cause skin irritation. Wear gloves when handling this plant. And once you remove the gloves, be sure to thoroughly wash your hands.

Conclusion

If you’re looking for an easy-to-care-for plant that is still visually appealing, the pencil cactus is a great choice.

Just make sure to place it in a bright spot indoors, and water it when the soil is completely dry.

Be mindful when handling this plant, as the sap can cause skin and eye irritation. Keep it out of reach of children and pets, as it is poisonous if ingested.

With these simple guidelines, you’ll have a happy and healthy pencil cactus!