Creosote bush is a flowering shrub native to the southwestern region of North America. As the name implies, this plant has a strong odor of creosote — the oily fluid resulting from the burning of coal and wood tar, often used as an antiseptic or wood preservative — especially after rains. It is a common feature in North American deserts and many residents of the region are familiar with the appearance and odor of the plant. Also known as chaparral, creosote bush has historically been used in herbal medicine, but it can cause severe liver and kidney toxicity, and this usage is not recommended today.
Larrea tridentata, as it is known to scientists, produces woody branches and evergreen leaves. The leaves are small and waxy, and may drop off when the plant is under stress, as in severe droughts. The flowers of the creosote bush are yellow, and develop into white puffs of seeds. On plants of varying ages, it is sometimes possible to see a gall, a growth caused by insect colonization and subsequent inflammation. Galls are common growths on a variety of plants and sometimes yield dyes and other useful compounds.
Like other desert plants, creosote bush is extremely drought tolerant. It can be used successfully in low water gardening and xeriscaping, and takes readily to shaping by pruning, allowing people to control the appearance and growth habits of the plant. Creosote bush prefers full sun and gardeners should be aware that the plant has developed some interesting methods of limiting competition. Creosote bushes put out chemicals to kill plants near their roots, ensuring that they get enough water. This trait is not uncommon in plants native to desert regions.
Creosote bushes can live to be hundreds or thousands of years old. As plants age, they produce clones of themselves as older branches die off and their young tips root. This creates a distinctive ring-shaped growth habit as the clones take root and the parent plant dies off. One clonal colony, known as King Clone and located in California, was estimated to be almost 12,000 years old when it was originally identified in the late 20th century.
People interested in growing creosote bush will need to live in hot, harsh, dry climates. Throughout the plant's native range, it can be cultivated as an ornamental, and may be used for specimen plantings and hedges. When seedlings are initially established, they should be given some watering support to allow them to take root and develop. After the first several weeks, however, the plants tend to thrive on benign neglect and periodic pruning, if desired.