The Crown of Thorns (Euphorbia milii) is a popular succulent known for its bright bracts and thorny stems, but it often develops a long, single stem, a growth habit known as “legginess.” This upward growth is due to apical dominance, where a hormone called auxin, produced at the growing tip, suppresses the development of side buds. Encouraging a dense, bushy form is achieved by systematically removing this dominant growth point, which forces the plant to redirect energy laterally. This intervention stimulates dormant buds along the stem to develop into new branches.
Strategic Pruning for Lateral Growth
Encouraging branching relies on eliminating the plant’s natural tendency toward vertical growth. Pruning disrupts apical dominance, signaling the plant to distribute growth hormones to lower buds. This redistribution of internal resources causes the plant to become bushier, as multiple new shoots emerge.
The best time to prune is during the plant’s active growing season, typically in late spring or early summer, when it has the energy reserves to quickly heal and initiate new growth. Always use a clean, sharp tool like a sterile knife or bypass pruners to make a swift, precise cut, which minimizes damage to the stem tissue. Because the plant’s sap is a skin irritant, protective gloves and eyewear are strongly recommended.
To achieve the desired shape, locate a leaf node or a dormant bud on the stem and make your cut just above that point. New branches will emerge from the axillary buds located there. The amount of stem removed depends on the height and density you wish to achieve, but even removing the topmost growing tip, or “pinching,” can be effective. You can expect two or three new lateral branches to develop near the cut site, creating a fuller appearance.
Essential Environmental Conditions for Success
While pruning is the catalyst for branching, the plant’s environment determines the strength and success of the new growth. A stressed plant will produce weak, sparse branches, so providing optimal growing conditions is a necessary follow-up. The most significant requirement for robust, multi-branched growth is abundant light exposure.
Crown of Thorns needs bright, direct sunlight for several hours a day to support the energy demands of multiple new stems and prolific flowering. Insufficient light will cause the new shoots to become thin and elongated, quickly returning the plant to a leggy state. Placing the plant in a south-facing window or a location that receives at least six hours of direct sun is necessary for the best results.
Warm temperatures are also necessary to keep the plant in its active growth phase, as it will slow down or enter dormancy if temperatures drop consistently below 60°F. The ideal temperature range for maximum growth is between 65°F and 75°F. Watering should be managed carefully, allowing the soil to dry out completely between thorough waterings, a practice that mimics its native arid habitat and prevents root rot.
Encouraging New Growth After Cutting
The immediate aftercare following pruning focuses on managing the milky white sap and providing necessary nutrients for new buds to form. When a cut is made, the plant releases a toxic latex sap that should be handled with caution. To stem the flow and encourage the wound to seal, dab the cut surface with cold water, or apply a small amount of powdered horticultural charcoal or sulfur powder.
This sealing process is important for preventing potential fungal issues and promoting the formation of a protective callus layer. Once the wound has begun to heal, providing the right balance of nutrients will help push the dormant buds into active growth. A balanced, water-soluble fertilizer, such as a 10-10-10 or 20-20-20 formula, should be applied at half-strength every four to six weeks during the active growing season.
Alternatively, a fertilizer slightly higher in phosphorus may be beneficial, as this element supports both root and flower development. Monitor the area just below the cut for the development of small, swelling buds. These are the first sign that the plant has successfully redirected its energy for lateral growth.