How to Grow and Care for Pencil Milk Bush
A practical guide to growing a healthy Pencil Milk Bush. Learn its specific needs, how to address common issues, and essential safety information.
The Pencil Milk Bush, Euphorbia tirucalli, is a distinctive succulent also known as Pencil Cactus, Indian Tree Spurge, and Firesticks. Native to southern and eastern Africa, this popular houseplant is known for its unique structure. It grows with a thick trunk and primary branches that give way to clusters of slender, pencil-like green stems. While it can reach 30 feet in its natural habitat, it grows between 2 and 6 feet tall indoors. The plant’s small leaves appear at the tips of new growth but fall off quickly, leaving the green branches to perform photosynthesis.
Pencil Milk Bush Care
Light
For healthy growth, Euphorbia tirucalli requires a significant amount of sunlight. A south-facing window is ideal, as this provides the direct sun it needs. Sufficient light also enhances coloration, especially in cultivars like ‘Firesticks’, whose stems develop a vibrant red-orange hue in response to intense sun. While bright, indirect light will sustain the plant, full sun encourages the most robust appearance. During summer, it can be moved outdoors to a bright location.
Soil
A well-draining substrate is necessary to avoid waterlogging, as this plant is sensitive to root issues. Commercial cactus or succulent mixes are well-suited for this purpose because they provide proper drainage. Alternatively, you can create your own mix using coarse loamy soil, peat moss or leaf mold, and a gritty material like coarse sand.
Water
Use the “soak and dry” method for watering. Water the plant thoroughly until it runs out of the drainage holes, then allow the soil to dry out completely before watering again. During the winter dormant phase, reduce watering significantly. Always err on the side of underwatering this drought-tolerant succulent to prevent issues.
Temperature and Humidity
The Pencil Milk Bush prefers warm, dry conditions and thrives in temperatures between 68°F and 86°F (20°C to 30°C). It is not frost-tolerant and must be protected from temperatures below 54°F (12°C). This plant is well-suited to the low humidity found in most homes and does not require additional air moisture.
Fertilizer
During the spring and summer growing season, the Pencil Milk Bush benefits from occasional feeding. Apply a balanced, water-soluble fertilizer diluted to half-strength once a month. Stop fertilizing entirely during the fall and winter dormancy period.
Toxicity and Handling Precautions
Euphorbia tirucalli is not a true cactus but a member of the spurge family. A defining characteristic of this family is the milky white latex sap that exudes when any part is broken or cut. This sap is toxic and can cause adverse reactions. Direct contact with the skin can lead to irritation, while contact with the eyes may cause severe pain and temporary blindness.
If ingested, the sap is poisonous to both humans and pets. For this reason, always wear gloves and protective eyewear when pruning, repotting, or taking cuttings. The plant should also be placed in a location safely out of reach of children and animals to prevent accidental exposure.
Propagating Pencil Milk Bush
Propagating the Pencil Milk Bush is done using stem cuttings. It is important to wear protective gloves to avoid the sap. Select a healthy stem and cut a section that is at least 4 to 6 inches long. Allow the cutting to sit in a dry, well-ventilated area for several days. This drying period is for the cut end to form a callus, which prevents the cutting from rotting when planted.
Once the callus has formed, place the cutting into a pot with a well-draining soil mix, similar to the parent plant. Water the new cutting sparingly until it establishes a root system, which can take a few weeks.
Common Issues and Solutions
Yellowing or mushy stems are a frequent problem and a clear indicator of root rot. This is caused by overwatering or soil that does not drain properly. If you notice this, reduce watering and ensure the pot has adequate drainage. In advanced cases, you may need to repot the plant into fresh, dry soil after trimming away any rotted roots.
If your plant is stretching with elongated stems and fading color, a process known as etiolation, it is not receiving enough light. To resolve this, move the plant to a location where it can receive more direct sunlight. While resilient to pests, the Pencil Milk Bush can be affected by mealybugs, spider mites, or aphids. These pests can be treated by wiping them off with a cotton swab dipped in rubbing alcohol or by applying neem oil or insecticidal soap.