Creosote Bush (Larrea tridentata) is an evergreen, flowering shrub that is named for its fragrant aroma. Creosote bush is said to smell like creosote and is often associated with the smell of rain. Its yellow flowers bloom during spring and throughout the year. This species grows best in full sun and tolerates a variety of soil conditions.
I. Appearance and Characteristics
Larrea tridentata, called creosote bush and greasewood as a plant, chaparral as a medicinal herb, and gobernadora (Spanish for “governess”) in Mexico, due to its ability to secure more water by inhibiting the growth of nearby plants. In Sonora, it is more commonly called hediondilla; Spanish hediondo = “smelly”.
It is a flowering plant in the family Zygophyllaceae. The specific name tridentata refers to its three-toothed leaves.
Larrea tridentata is a prominent species in the Mojave, Sonoran, and Chihuahuan Deserts of western North America, and its range includes those and other regions in portions of southeastern California, Arizona, southern Nevada, southwestern Utah, New Mexico, and Texas in the United States, and Chihuahua, Sonora, Coahuila, Nuevo León, Zacatecas, Durango and San Luis Potosì in Mexico. The species grows as far east as Zapata County, Texas, along the Rio Grande southeast of Laredo near the 99th meridian west.
Larrea tridentata is an evergreen shrub growing to 1 to 3 m (3 to 10 ft) tall, rarely 4 m (13 ft). The light gray stems of the plant bear resinous, dark green leaves with two opposite lanceolate leaflets joined at the base, with a deciduous awn between them, each leaflet 7 to 18 mm (1⁄4 to 11⁄16 in) long and 4 to 8.5 mm (5⁄32 to 11⁄32 in) broad. The flowers are up to 25 mm (1 in) in diameter, with five yellow petals. The fruit is a brown-burgundy spherical, fuzzy capsule, which separates into five individual carpels each containing one seed. Galls may form by the activity of the creosote gall midge. The whole plant exhibits a characteristic odor of creosote, from which the common name derives. In the regions where it grows, its smell is often associated with the “smell of rain”.
Creosote bush is most common on the well-drained soils of alluvial fans and flats. In parts of its range, it may cover large areas in practically pure stands, though it usually occurs in association with Ambrosia dumosa (burro bush or bur-sage). Chemicals found in creosote bush roots have been shown to inhibit the growth of burro bush roots, but as of 2013, much of their relationship remains unexplained.
Creosote bush stands tend to display an evenly spaced distribution of plants. Originally, it was assumed that the plant produced a water-soluble inhibitor that prevented the growth of other bushes near mature, healthy bushes. Now, however, it has been shown that the root systems of mature creosote plants are simply so efficient at absorbing water that fallen seeds nearby cannot accumulate enough water to germinate, effectively creating dead zones around every plant.
II. How to Grow and Care
Creosote bush is a resilient and low-maintenance plant, thriving in harsh desert environments. Key care points include ensuring full sun exposure and maintaining a dry, well-drained soil as creosote bush is highly drought-tolerant and sensitive to overwatering. It requires minimal supplemental watering, making its care relatively easy.
Sunlight and Soil
Creosote bush performs best in full sun, in rocky, sandy or gravelly soils. It needs supplemental water once a month in summer. And it is drought tolerant.
Watering
Creosote bush is a plant adapted to arid environments, demonstrating significant drought tolerance. It has evolved to survive with watering once every 1-2 weeks. As an evergreen shrub, creosote bush maintains its water content year-round by shedding leaves during dry periods and regrowing them when conditions improve.
Fertilizing
For optimal health, creosote bush benefits from twice-yearly fertilization using balanced nutrition fertilizers in spring and high nitrogen ones in late summer to support vigorous growth and resilience. Apply according to product label guidelines, cautioning against over-fertilization which can harm its native-adapted efficiency. Seasonal adjustments in quantity ensure the creosote bush receives adequate nutrients without disrupting its natural adaptations.
Propagation
Creosote bush propagates optimally during spring and summer through cutting. Moderate difficulty may be encountered, but successful propagation is indicated by new leaf growths. Consider providing a warm, well-lit environment for enhanced chances of success.
Transplanting
The optimal time to relocate creosote bush is during the onset of warmer days at the close of winter, fostering better adaptation. Choose a sunny, well-drained spot and acclimate it gently to minimize shock.
Repotting
Repot the resilient creosote bush every 2-3 years, ideally in the spring. As a large, shrub-like plant, it requires ample space to thrive. Opt for a wide, deep pot that accommodates its extensive root system. Post-repotting, place creosote bush in full sun, ensuring minimal care as it adapts. This desert native prefers infrequent watering, matching its hardy nature.
III. Uses and Benefits
- Native American medicinals
Native Americans in the Southwest held beliefs that it treated many maladies, including sexually transmitted diseases, tuberculosis, chicken pox, dysmenorrhea, and snakebite. The Coahuilla Indians used the plant for intestinal complaints and tuberculosis. The Pima drank a decoction of the leaves as an emetic, and applied the boiled leaves as poultices to wounds or sores. Tohono O’odham Indians prepared it medicinally for stiff limbs, snake bites, and menstrual cramps. The shrub is still widely used as an herbal medicine in Mexico.
In other uses, the reddish-colored lac that exudes from the plant was used by the Tohono O’odham, after boiling, to make a mending glue on broken pottery.
- Herbal supplements and toxicity
Larrea tridentata is often referred to as chaparral when used as a herbal remedy and supplement; however, it does not grow in the synonymous plant community chaparral. The United States Food and Drug Administration has issued warnings about the health hazards of ingesting chaparral or using it as an internal medicine, and discourages its use. In 2005, Health Canada issued a warning to consumers to avoid using the leaves of Larrea species because of the risk of damage to the liver and kidneys.
