A milk bush is a shrub that is native to northeastern, southern, and central Africa and that also grows throughout other semi-arid tropical regions, including parts of India. Known by many other names, including pencil cactus, firestick plant, and Indian tree spurge, the plant can reach a height of between 12 and 20 feet (3.6 and 6 meters). The plant can be used for several purposes, such as hedging, cattle feed, and medicinal uses. In addition, the milk-like latex produced by this African shrub can be converted into a fuel that is very similar to gasoline. Gardeners in semi-arid climates also grow milk bush as a houseplant or outdoors as part of their landscaping.
The typical milk bush plant is similar in appearance to a cactus, but without spines. The branches grow in a pseudo whorl pattern and produce small, deciduous leaves. Yellow flowers may bloom at the ends of branches, usually in the spring.
The milk bush is classified as a tropical or tender perennial. It is hardy in USDA zones nine to 11 and prefers full sun and soil with a pH of between 6.1 and 7.8. This plant can be grown indoors in a container or outdoors and is resistant to drought. It is vulnerable to both the mealy bug and scale.
The plant is a common source of cattle feed throughout India. Milk bush is also used as hedging or as natural fencing. Firewood and mosquito repellent are additional uses of the cactus-like plant in Brazil and Africa.
As of 2010, there is interest in growing this plant as a possible source of fuel. The sap can be converted into a substance similar to gasoline. The plant can grow on land that is otherwise not used for crops, and the yield from an acre of this African shrub is comparable to that of other biodiesel sources.
Traditional medicine practices in places like Brazil, India, and other parts of Asia have relied on this plant to treat a variety of ailments. Warts, asthma, and ear pain are sometimes treated with milk bush. Additional diseases that are said to be relieved by milk bush are rheumatism and neuralgia. It has also been studied as a possible cancer treatment.
The sap produced by this plant is poisonous if consumed and can irritate human skin. Contact with eyes can cause temporary blindness, and some individuals have even reported experiencing anaphylactic shock following contact. As a result, this plant may not be suitable for homes with pets or small children and is also toxic to small animals such as rabbits.