The “Devil’s Horns Plant” is a common name that often leads to confusion, as it most frequently refers to Euphorbia milii, widely recognized as the Crown of Thorns. This resilient plant is celebrated for its distinctive thorny stems and bright, petal-like structures known as bracts, which are often mistaken for flowers. Its striking appearance and relatively straightforward care requirements have made it a popular choice for both indoor enthusiasts and outdoor gardens in suitable climates. The Crown of Thorns is valued for its ability to provide vibrant color year-round.
Identifying the “Devil’s Horns” Plant
The plant specifically identified as the “Devil’s Horns Plant” in horticulture is Euphorbia milii, also known by its more common name, Crown of Thorns. This succulent shrub is characterized by its thick, woody stems densely covered with sharp, grey to brown spines that can reach up to an inch in length.
While the actual flowers are small and inconspicuous, located at the center of specialized structures called cyathia, they are surrounded by prominent, colorful bracts. These showy bracts come in a wide array of colors, including various shades of red, pink, yellow, and white, giving the plant its ornamental appeal. Euphorbia milii is native to Madagascar, where it grows in rocky, dry habitats, and has adapted to thrive in a range of conditions.
Caring for Your “Devil’s Horns” Plant
Light
Crown of Thorns plants thrive in bright, direct sunlight, requiring at least five to six hours daily for optimal growth and prolific blooming. While they can tolerate some partial shade, such conditions typically result in fewer flowers. For indoor cultivation, placing the plant near a south- or west-facing window provides the consistent light exposure it needs. In outdoor settings, ensuring the plant receives full to partial sunlight, ideally around four to six hours, will encourage robust health and abundant blooms.
Watering
As a succulent, Euphorbia milii is notably drought-tolerant, storing water within its thick, spiny stems. The most effective watering strategy involves allowing the soil to dry out completely between waterings to prevent issues like root rot. During the active growing seasons of spring and summer, watering approximately once every seven to ten days may be necessary, depending on environmental factors. However, in fall and winter, when the plant enters a semi-dormant phase, watering frequency should be significantly reduced to about once every three to four weeks. Always use room temperature water to avoid shocking the plant’s root system.
Soil and Potting
Selecting the correct soil is important for the health of Euphorbia milii, as it requires excellent drainage to prevent waterlogging and root rot. A specialized cactus or succulent potting mix is highly recommended, as these are formulated to drain efficiently. If using a regular potting mix, it can be amended with materials like perlite or coarse sand to improve aeration and drainage. Additionally, choosing a pot with adequate drainage holes is non-negotiable, ensuring excess water can escape freely from the container. This mimics the arid conditions of its native habitat, promoting strong root development.
Temperature and Humidity
Crown of Thorns plants prefer warm conditions, thriving in temperatures generally ranging from 65°F to 95°F (18°C to 35°C). They are not tolerant of cold temperatures and can suffer damage if exposed to conditions below 50°F (10°C). It is advisable to protect them from cold drafts or sudden temperature fluctuations, which can stress the plant. Fortunately, Euphorbia milii adapts well to typical household humidity levels and does not require additional moisture, making it a suitable houseplant for most home environments.
Fertilizing
To support vigorous growth and consistent blooming, Euphorbia milii benefits from fertilization during its active growing season, typically spanning spring and summer. A balanced liquid fertilizer, diluted to half strength, is appropriate for feeding. Applying fertilizer approximately every two to three months during this period provides the necessary nutrients for flower production. During the plant’s dormant phase in winter, withhold fertilizer completely. Over-fertilization can sometimes lead to an abundance of foliage at the expense of fewer flowers.
Common Issues and Solutions
A common concern for Euphorbia milii is a lack of blooms, primarily linked to insufficient light. Moving the plant to a brighter location, such as a south or west-facing window, usually resolves this. Sometimes, too much artificial light at night or excessive fertilization can also inhibit flowering. Leaf drop can occur from stress due to sudden temperature changes or inconsistent watering.
Root rot is caused by overwatering or poorly draining soil; ensure the soil dries out completely between waterings and use a well-draining succulent mix. Pests such as mealybugs, spider mites, aphids, or scale can occasionally affect the plant. These can often be managed with general organic pest control methods like neem oil or insecticidal soap. Leggy growth, characterized by stretched stems with sparse leaves, indicates insufficient light; pruning can encourage a more compact form.
Propagating “Devil’s Horns” Plant
Propagating Euphorbia milii is commonly achieved through stem cuttings. Wear gloves when taking cuttings to protect against the irritating milky sap. Healthy stem sections, typically three to six inches long, should be cut from the plant. Allow the cut end to dry and form a callus for two to three days before planting.
Once callused, plant the cutting about an inch deep into a well-draining soil mix, such as a cactus or succulent blend. Providing a warm environment, ideally between 75-80°F (24-27°C), and indirect light will promote root development. Keep the soil slightly moist until roots establish, usually within three to six weeks.
Safety Considerations
When handling Euphorbia milii, be aware of its safety considerations. The plant produces a milky white sap, or latex, when its stems are cut or damaged. This sap contains irritant compounds that can cause skin irritation, including dermatitis and blistering, upon contact. If the sap contacts the eyes, it can lead to severe pain and inflammation.
The sap is also toxic if ingested, posing a risk to humans and animals. Wear gloves when handling the plant to minimize exposure. Place Euphorbia milii out of reach of small children and pets. Its sharp thorns also require careful handling.