Common Name: Creosote Bush

General Information

Larrea tridentata is an evergreen shrub that usually grows around 100 - 150cm tall but can reach 300cm[].
The plant is harvested from the wild for local use as a food and medicine. It is grown as an ornamental in arid areas.

Known Hazards

The plant is rich in resins and is generally unpalatable to grazing animals, and is usually toxic, sometimes causing death[].
There is some concern over the potential toxic effect of this plant upon the liver[]. There have been a number of cases of acute or sub-acute hepatitis attributed to the medicinal use of this herb and so its internal use is not recommended until further research has been carried out[].

Botanical References

Range

South-western N. America - California, Nevada, Utah, Arizona, New Mexico, Texas, northern and central Mexico

Habitat

Deserts, usually in open, species-poor communities, sometimes in pure stands; also transitional in desert grasslands, viscid acacia-mariola chaparillo, mesquite woodlands, Joshua tree-big galleta communities, and xeroriparian areas[]

Properties

Edibility Rating
Medicinal Rating
Other Uses Rating
Habit	Evergreen Shrub
Height	4.00 m
Pollinators	Bees, Insects
Self-fertile	Yes
Cultivation Status	Ornamental, Wild

Cultivation Details

Larrea tridentata is a plant of arid to desert regions. It is not very cold-hardy, especially in moister climates, usually tolerating short periods when temperatures fall as low as -5 to -10°c[]. In its desert environment temperatures can range from as high as 47°c in the summer down to -15°c in the winter[]. Mean annual rainfall ranges from 100 - 300mm[].
Requires a moderately fertile moisture-retentive soil in full sun or light shade[]. Plants grow in the wild on calcareous, sandy, and alluvial soils that are often underlain by a caliche hardpan[]. Established plants are drought-tolerant[]. When drought is extreme, old branches and roots die back, then when the rains return, the branches are replaced by sprouts originating near the outside of the root crown. With time, the plant (or more accurately its clones) gradually expands to form rings many meters in diameter[]
Plants are not very tolerant of fire, with most of them being killed even by low-intensity fires[].
The plant is resinous and very aromatic[, ].
A very long-lived plant, some individuals are known to be several thouand years old, and the average longevity of plants in one site was estimated to be around 1,250 years[].

Edible Uses

The flower buds are pickled in vinegar and used as a caper substitute[].

The stems and leaves are a tea substitute[].

The twigs are chewed to alleviate thirst[, ].

A resin is obtained from the leaves and twigs, it delays or prevents oils and fats from becoming rancid[].

Medicinal

Creosote bush was widely used by various North American Indian tribes. A decoction of the leaves was used to treat diarrhoea and stomach troubles whilst the young twigs were used to treat toothache and a poultice of the leaves was used to treat chest complaints and as a wash for skin problems[]. It continued to be widely used as a treatment for rheumatic disease, venereal infections, urinary infections and certain types of cancer, especially leukaemia until its sale was banned in North America due to concern over its potential toxic effect upon the liver[]. There have been a number of cases of acute or sub-acute hepatitis attributed to the use of this herb and so its internal use is not recommended until further research has been carried out[].
A tea made from the leaves is used as an expectorant and pulmonary antiseptic[].

Some N. American Indian tribes heated the shoot tips of this plant and dripped the sap (probably the resin[]) into tooth cavities to treat toothache[].

The plant contains phototoxins in its leaves that inhibit the growth of Escherichia coli and Saccharomyces cerevisiae cultures[].
One of the principal compounds in creosote bush resin is the anti-oxidant nordihydroguaiaretic acid (NDGA). This is a phenolic aglycone and comprises 5 - 10% of leaf dry weight, 80% of all phenolics in the resin, and once was used as an antioxidant in foods, pharmaceuticals, and industrial materials. NDGA has demonstrated an ability to inhibit tumors and cancers but does have toxic side effects to both animals and humans. Its use as a chemoprevention for skin cancer and protection against the effects of ultaviolet light has been investigated[].

Agroforestry Uses:

The plant may be used to rehabilitate disturbed environments in desert areas Once established, it improves sites
for annuals that grow under its canopy by trapping fine soil, organic matter, and symbiont propagules. It may also increase water infiltration and storage[]

Other Uses

The plant is host to an insect, Tachardiella larreae, which produces lac and deposits it on the stems of the plant. Lac is plastic when heated but hardens again on cooling, forming a strong bond like commercial sealing wax. Lac has been used by desert peoples to seal lids on food jars, repairing pottery, fastening arrow points, waterproofing baskets, and making mosaics[, ].

Propagation

Seed - viability rates of fresh seed ranges from 15 - 76% - leaching the seeds in running water for 12 hours prior to sowing has been shown to improve germination rate. Sowing the seed in shade, or even in darkness is more effective than sowing in a light positions[].. We have no further information but suggest sowing the seed in a greenhouse in spring. When they are large enough to handle, prick the seedlings out into individual pots and grow them on in the greenhouse for at least their first winter. Plant them out into their permanent positions in late spring or early summer, after the last expected frosts.
Cuttings of new growth in spring in a frame[].