How to Care for Pencil Cactus

Native to semi-arid regions of Africa and India, the Pencil Cactus (Euphorbia tirucalli) is a distinctive succulent shrub known for its slender, pencil-like green stems that give it its common name. Unlike most cacti, it belongs to the Euphorbia family and produces a milky white sap. Its sculptural form and minimal foliage make it a bold, modern accent for homes and offices. Thanks to its hardy nature and drought tolerance, it’s well-suited for plant lovers who prefer low-maintenance greenery.

The Pencil Cactus has extremely low water needs, making it one of the easiest plants to care for. With easyplant, simply check the reservoir once every three months and refill it when empty - that’s all it takes to keep your plant thriving.

Pencil Cactus grows best in a space with bright direct light, where the sunlight streams inside directly, and can also adapt to spaces with bright indirect light, where the sun rays are diffused. Avoid placing it in spaces with low light or spaces without natural sunlight.

The Pencil Cactus is remarkably low-maintenance, making it an excellent choice for both new and experienced plant owners. Rotate the pot by a quarter turn every month or so to encourage even growth and prevent it leaning towards the light. Pruning is rarely necessary, but if you’d like to control its shape or size, trim sparingly using clean, sharp scissors. Always handle with care when pruning, as the plant releases a milky sap that can be an irritant to skin and eyes - gloves are recommended. With just occasional attention, this plant will thrive and bring unique, sculptural greenery into your home.

The Pencil Cactus is a fast grower when given the right conditions. Indoors, it typically reaches between 6 and 10 feet in height, though it can be pruned to maintain a more manageable size. Outdoors in its native environment, this plant can grow into a full tree of up to 30 feet tall. Growth speed indoors depends largely on light exposure - with bright, consistent light, you can expect noticeable new growth each year. Its slender, branching stems add height and structure without taking up much horizontal space, making it an impressive yet space-efficient choice for your home.

The Pencil Cactus thrives in warm, dry conditions similar to its native habitat. The ideal indoor temperature range is 65–80°F, and it should never be exposed to temperatures below 50°F, as prolonged cold can damage the plant. It adapts well to average household humidity and doesn’t need any extra moisture in the air. In fact, overly humid conditions can encourage rot, so it’s best to keep this plant in a drier environment. Avoid placing it near air-conditioning vents or cold drafts, which can cause stress.

Yes - the Pencil Cactus is highly toxic to both pets and humans. It contains a white, milky latex sap that can cause serious irritation. If touched, the sap may lead to skin inflammation or eye discomfort, and if ingested, it can result in nausea, vomiting, and more severe digestive issues. This sap is especially dangerous for pets like cats and dogs, who may chew on the plant or get the sap on their fur and then groom themselves.

Because of its toxicity, it’s important to keep the Pencil Cactus out of reach of children and animals, and to always wear gloves when pruning or repotting. If any sap comes into contact with skin or eyes, rinse thoroughly with water and seek medical attention if needed.

Most Pencil Cactus issues trace back to watering or light. If stems look soft, mushy, or dark at the base, that’s almost always overwatering - let the mix dry out completely, empty any standing water, and hold off before the next refill (with easyplant, it's much easier - only refill the reservoir once every three months).

Pale, stretched, or floppy growth signals not enough light; move it to a brighter spot with several hours of sun. Sudden bleached patches or crisp tips usually mean it went from low light to intense sun too quickly - ease it into brighter exposure over a week.

Wrinkled, shriveling stems indicate it’s gone too dry for too long; give a thorough drink, then let excess water drain. Cold drafts can cause stress and stall growth, so keep it away from AC vents and winter chills.

Watch for pests - mealybugs (cottony tufts), scale (sticky residue or bumps), and spider mites (fine webbing). If you notice them, wipe affected areas with isopropyl alcohol, then follow up with insecticidal soap or neem oil, repeating weekly until clear.

If you prune or accidentally nick a stem, it will ooze a milky latex sap that can irritate skin and eyes; wear gloves, avoid contact, and allow cuts to callus before the next watering.