The Pencil Cactus (Euphorbia tirucalli) is a shrub or small tree with woody, toxic sap and a unique, decorative appearance. Its stem is upright and branched, with a succulent texture when young, gradually becoming woody. The branches are cylindrical, green, and whorled, playing the role of photosynthesis for the plant. They are generally green but acquire beautiful orange and reddish hues under strong sunlight. The leaves are sparse and sometimes absent, small, alternate, fleeting, and appear at the tips of young branches. Inflorescences are terminal cymes, forming tight racemes of subsessile cyathia. The flowers or cyathia are terminal, small, and of little ornamental importance.
In landscaping, the Pencil Cactus is an excellent choice for desert-inspired or rocky gardens. It serves as a “background” for other more strikingly shaped and colored succulents and cacti. Additionally, it allows for shaping pruning and can be used as an efficient hedge. It can also be planted in pots and planters. Due to its tolerance to coastal salt, it is an interesting option for beach gardens. Fun fact: Chemist Melvin Calvin demonstrated that it is possible to convert the sap of the Pencil Cactus into gasoline in a simple way. Furthermore, he estimated that its yield would be 10 to 50 barrels of oil per hectare. Currently, oil companies like Petrobras are investing in research on its cultivation and chemical transformation.
The milky sap of the Pencil Cactus is very toxic, yet it is considered important in the traditional medicine of cultures in India, Africa, Indonesia, Malaysia, and even Brazil. It is used to treat various ailments, from warts to cancer and even AIDS. Some important and respected research institutions have already proven the benefits of the Pencil Cactus in cancer treatment. However, the mechanism of action of the plant’s therapeutic substances is still not well understood. Do not use this plant without medical guidance.
It should be cultivated in full sun in various types of soil, preferably well-drained and sparsely irrigated. It thrives even in poor soils, but fertilization will allow for a more lush and beautiful plant. Drought tolerant. It does not withstand intense cold or frost. During the cold winter, reduce watering. It propagates by cutting branches, which are rooted in a well-drained substrate year-round. It is important to let the branches stop the sap flow before planting.
