Botanical Name — Euphorbia trigona
Common Name — African milk tree, Cathedral cactus
Plant Family — Euphorbiaceae
Originating in Central Africa, Euphorbia trigona is a cactus-like plant bearing a main upright stem with several smaller branches. This is an easy-care beautiful ornamental plant that would grow well indoors or outdoors.
- African milk tree plants do best in full sun, at least 5 to 8 hours a day. Avoid intense afternoon sun. Grow outdoors in light shade or indoors in a sunny window with southern exposure and direct sun.
- Euphorbia trigona prefers warm temperatures in the 70s and 80s. In can become stressed if left in conditions of extreme temperatures or intense sun.
- These plants are not cold hardy if grown outdoors migrate these plants to a sunny spot indoors when nighttime temperatures drop below 55 ºF.
- Native to arid and sub-tropical climates Euphorbia trigona are drought-tolerant plants. Their soil should be allowed to dry out entirely before watering thoroughly.
- These plants prefer a sandy, sharply draining mix. Cacti or succulent potting mix is great. You can amend a regular potting soil with sand or pumice up to 50% to improve grittiness and drainage.
- Euphorbia have very shallow root systems. Mature plants can be quite top-heavy. Consider adding a layer top dressing such as lava rocks to cover the soil and provide extra weight to prevent the plant from toppling over, or using a stake to keep the plant upright.
- These plants produce small white or yellow flowers during the spring and summertime. Potted plants and plants grown indoors rarely flower.
- These plants do not require fertilizer though it can be added to give container-grown plants a boost or to supplement poor soil. Apply a water-soluble, balanced fertilizer monthly, diluted at half strength.
- African milk tree plant can be propagated from stem cuttings. Take great care when cutting these plants as they contain a sap that can be highly irritant if contacted with skin.
- Allow cuttings to callous for several days before dusting with rooting hormone and placing in soil.
- Euphorbia trigona are not prone to pests. Though not super common, they are more likely to fall victim to bacterial or fungal infections. Look out for unusual spotting on stems and remove any affected parts of the plant.
- If the infection has not spread, the affected area can be cut away and the rest of the plant can be salvaged. Infections that have spread throughout the plant are more difficult to treat or mitigate and the entire plant may need to be destroyed.
- Root rot can also be a concern and is triggered by overwatering. Always err on the side of underwatering.
Maintenance (pruning, legginess, repotting)
- Little maintenance is required to grow these plants. Pruning is only necessary if parts of the plant are unhealthy or damaged.
- These plants have very shallow root systems, and thus do not require frequent repotting.
- All Euphorbia plants contain a poisonous sap that is very toxic if ingested and highly irritant if contacted with skin. Keep out of reach of pets and children. Wear gloves and take great care when handling this plant.