Euphorbia tirucalli
Indian Tree Spurge, Pencil Tree, Milk Bush, Fire Sticks, Sticks on Fire, Aveloz
Africa & India | Tropical (semi-arid)
A strange plant that might seem more at home in a coral reef. The tangle of stems and branches have a uniform thickness that happens to resemble a pencil—hence the name! But another name, Fire Sticks, hints at a show-stopping ability to change color. The stems can shift from a vibrant green to yellow, orange, and pink!
arid or semi-arid, cactus or succulent, color, easy going, drought tolerant, direct, upright, floor, tabletop, tropical, clusters, mid-size
Water thoroughly when soil is about 50% to entirely dry. Avoid overwatering at all costs. Watering may be even less frequent during winter months or in less light.
Primarily plenty of bright, indirect light with a few hours of direct light is ideal for a happy, thriving plant.
While not at all bothered about high humidity, your Pencil Cactus may appreciate the occasional misting, which helps remove dust.
Loves the heat! Will do most of their growth in temps over 70°F. Can tolerate lower temperatures, but will not grow as much.
The Pencil Cactus is highly toxic to pets and humans. Contact with the milky sap has been known to result moderate to severe allergic reactions (related to latex sensitivities). Consider wearing gloves when tending to this plant. Keep away from children and pets and wash your hands after handling.
Indoors, this plant can grow up to around 6 ft tall with a 2 ft spread (when mature and with enough light)!
The dense stems with plentiful branches of a uniform thickness create a coral-like effect. This effect is accentuated by the plant's color changing abilities.
The bright green stems are distinguished by their uniform thickness which happens to resemble the thickness of a pencil (hence the name) and their ability to change color. When exposed to bright enough light and cooler temperatures, the ends of the green stems are tinged in shades of pink, orange, and yellow.
While commonly known as a Pencil Cactus, it is actually classified as a stem succulent Euphorbia. Unlike a true cactus, Euphorbia have leaves and thorns rather than areoles and spines (modified leaves). Euphorbia are also distinct in that they produce a white, latex sap.
Water
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Allow half of soil to dry out before watering again.
Water thoroughly when soil is about 50% to entirely dry. Avoid overwatering at all costs. Watering may be even less frequent during winter months or in less light.
Light
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Bright, indirect to direct light.
Primarily plenty of bright, indirect light with a few hours of direct light is ideal for a happy, thriving plant.
Humidity
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Not too concerned by humidity levels.
While not at all bothered about high humidity, your Pencil Cactus may appreciate the occasional misting, which helps remove dust.
Temperature
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Enjoys warmer temps.
Loves the heat! Will do most of their growth in temps over 70°F. Can tolerate lower temperatures, but will not grow as much.
Toxicity
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Highly toxic to humans and pets if ingested.
The Pencil Cactus is highly toxic to pets and humans. Contact with the milky sap has been known to result moderate to severe allergic reactions (related to latex sensitivities). Consider wearing gloves when tending to this plant. Keep away from children and pets and wash your hands after handling.
Size
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Pretty big, but manageable.
Indoors, this plant can grow up to around 6 ft tall with a 2 ft spread (when mature and with enough light)!
Format
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Dense clusters of many-branched stems.
The dense stems with plentiful branches of a uniform thickness create a coral-like effect. This effect is accentuated by the plant's color changing abilities.
Leaf Shape
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Tiny unremarkable leaves stud dense, plentiful stems.
The bright green stems are distinguished by their uniform thickness which happens to resemble the thickness of a pencil (hence the name) and their ability to change color. When exposed to bright enough light and cooler temperatures, the ends of the green stems are tinged in shades of pink, orange, and yellow.
Fun Fact
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Not officially a cactus.
While commonly known as a Pencil Cactus, it is actually classified as a stem succulent Euphorbia. Unlike a true cactus, Euphorbia have leaves and thorns rather than areoles and spines (modified leaves). Euphorbia are also distinct in that they produce a white, latex sap.
Thrives in an airy, light, fast-draining potting mix—you can use a good quality potting mix labeled for succulents/cactus or supplement a standard indoor mix with an equal quantity of pumice or horticultural grit. Ensure the pot has the appropriate drainage and don't forget to pour out any excess water collected in the drainage tray or cachepot.
Try to repot every 3-4 years in the spring, especially when tending to a younger plant. Increase the pot size by about 2 inches each time or until you're satisfied with the size. It's still important to repot at this stage, but it'll be an exercise of refreshing the soil, keeping the pot size the same, and possibly doing some root trimming to restrict the plant's growth. More on repotting here.
If you're not already planning to repot, you can fertilize during the spring and summer months. Once to every two months should be plenty. No fertilizer is necessary during the winter when plant growth naturally slows down. You can try a balanced liquid or water-soluble fertilizer—always diluted more than the recommended strength. A cactus and succulent specific feed would also work well. More on using fertilizer here.
While no specific pruning is required for this plant, it's always good practice to regularly remove yellowed or dying leaves and any fallen plant debris. Ensure your scissors or pruners are sanitized to avoid spreading disease or pests. More on grooming techniques here.
To propagate a Pencil Cactus, you can take stem cuttings, around 6 inches long. Rinse or wipe off the milky sap. To lessen the chance of rot, let the cutting callus over first by setting out on a dry surface. You can then pot up in a fast draining potting mix and you should see new buds forming soon! More on propagation techniques here.
Euphorbia is a large and diverse genus of plants (poinsettias are in there!), but the many of the euphorbias used as houseplants are originally from the deserts of Africa and evolved many physical characteristics and forms similar to the cacti of the Americas (thus the misleading common names). Beyond the Euphorbia tirucalli (Pencil Cactus), some of our favorites include Euphorbia trigona (African Milk Tree), Euphorbia lactea (Coral Cactus), Euphorbia ammak (Desert Cactus), and Euphorbia anoplia (Mother Hubbard).
Leaves are yellowing and soft, particularly around the base.
The most likely culprit is overwatering and initial signs of root rot. When a plant's roots sit in waterlogged soil for too long, a fungal infection can quickly take over, causing the roots to rot—turning brown and mushy.
First, ensure that your plant has appropriate drainage (both in terms of a well-draining soil and plenty of drainage holes in the plant's container).
If you think you've caught the overwatering early on, you can simply let the plant dry out more than you have been. Allow the top few inches of soil to dry out before watering again. Continue monitoring and only water when needed. You may also try using chopsticks (or something similar) to poke holes in the soil to help the roots get more oxygen. And finally, you can try to "wick" the excess moisture out of the soil by placing the whole pot (with drainage holes) in a tray or container with dry soil. This new layer of dry soil should soak up some of the excess moisture from the waterlogged areas around your plant's roots.
However, if you suspect a serious case of root rot, you'll definitely need to take a peak at the roots by removing the plant entirely from their container. If there are any black and mushy roots, trim them back completely before repotting with fresh soil in a new or sterilized container.
Stems are wrinkled or shriveled, but not soft or yellowing.
Wrinkling or shriveling of stems is often a sign of dehydration from either too much light or not enough water. If accompanied by softness or yellowing, this is more likely a sign of not enough light or too much water.
The key is a well tuned balance between the amount of light and your frequency of watering. Instead of going by a set schedule, check-in with your plant to see if they need the water or not. You'll want to allow around half the soil to dry out completely before watering again. While this may be on a consistent schedule for some months, as the seasons change, so will the amount of light and therefore your watering schedule must shift.
One or multiple stems feel a bit soft and may be starting to yellow or brown at the base.
This is a sure sign of persistent overwatering. The root rot has spread and led to stem rot as well.
You will have to cut back any stems with signs of rot. To avoid further spread, you should also take a peak at the roots by removing the plant entirely from their container. If there are any black and mushy roots, trim them back completely before repotting with fresh soil in a new or sterilized container.
Slow or no new growth. Possibly accompanied by pale new growth.
This is most likely due to insufficient light. Pencil Cactus are accustomed to receiving plenty of sunlight. Unlike most houseplants, they can generally withstand multiple hours of direct sun every day, something they'll be craving especially during the winter months.
Improve the lighting conditions for your Pencil Cactus to thrive. These plants prefer plenty of bright, indirect light along with a bit of direct light. Make sure to adjust your watering to accommodate the increased light.
