The gas plant, or Dictamnus albus, is a hardy perennial of the Rutaceae, or Rue family, and is native to southern Europe, northern Africa, and south central Asia. In the US it is generally hardy in the regions of the USDA Hardiness Zones three through eight. People call it the gas plant because of its volatile oils. The plant releases a lemon-scented oil as a vapor. On a calm, hot night, if a person holds a burning match near the flowers or stem, the vapor quickly ignites and the flame extinguishes itself.
The plant grows as a mounded bush, usually reaching a height and width of three feet (about one m), and gardeners often plant it as a border plant. Its glossy green foliage typically has the slight lemony odor like many plants in the Rue family and sets on star-shaped, brown seedpods in the fall. Generally, the gas plant grows best in a sunny location, with partial shade to protect it from scorching in the hottest regions, such as southern Florida and northern Africa. It usually produces loose pyramid-shaped spires of fragrant white, purple, or pink flowers. The color of the cup-shaped flowers depends on the cultivar.
Gardeners usually know the D. albus by several common names, including dittany, fraxinella, and burning bush. Burning bush also refers to Euonymus atropurpureus and E. americanus, which is a different family. The gas plant typically lives a long life and has outlived three generations of one family. Most gas plants cannot survive transplantation after the third year of growth; therefore, a gardener should choose the final site carefully.
One of the dangers of having gas plants in a garden is phytophotodermatitis, or PPD, a rash and possible blisters that people get from plant toxins and exposure to the sun. The plant sap causes the skin to be photosensitive and burn, and other plants in the Rue family have this same effect. Generally, experts advise gardeners to wear gloves, long-sleeved shirts, and long pants while pruning or working around these plants.
Various cultures use the gas plant for several folk medicines. Despite the plant's ability to cause PPD, some people use it topically for scabies, impetigo, and eczema, while others use it topically for arthritis, rheumatism, and joint pain. Sometimes people make an infusion from the leaves and flowers and use it to stimulate the uterine muscles, promote urine flow, and ease the cramping pain of constipation. Another herbal remedy uses dried root and bark mixed with peppermint to treat epilepsy, cramps, and fevers and to kill parasites.