Photo courtesy of Dr. James Bowns, Southern Utah University
Larrea tridentata (DC.) Cov.
Scientific Name Synonyms:
Life Span: Perennial
Growth Characteristics: A 3 to 13 foot tall tree with no well-defined trunk. It has numerous limber stems from near ground level. It is often scattered in nearly pure stands with little variation in size. Flowers February to August, depending on when rain falls, but it is usually in the spring. Reproduces from rhizomes and seeds, although regeneration by seed is rare. Plant has a creosote-like odor.
Flowers/Inflorescence: Flowers are solitary, with yellowish sepals and bright yellow petals.
Fruits/Seeds: Fruit is a capsule covered with dense white to red-wooly long hairs tipped by a thread like appendage. "A white fuzzy seed ball."
Leaves: Leaves and leaflets are opposite. Leaf surface is dark green to yellowish-green, glossy, and resinous (sticky). Leaflets are thick and sickle-shaped. The stipules at the base of the petiole are brown and hairy. Leaves are strongly scented.
Stems: Twigs are opposite, brown in color and slender, nodes somewhat swollen giving the plant a jointed appearance. Branches are brittle and densely leafy at the tips.
Creosotebush is found on alluvial plains, hillsides, mesas, and in deserts in the southwestern corner of Utah. It is drought tolerant and plants can be several thousand years old.
Creosotebush, through cloning, achieves its status as one of the most stable members of desert communities. When drought is extreme, old branches and roots of creosotebush die back. When rains return, branches are replaced by sprouts originating near the outside of the root crown. Creosotebush clones gradually expand to form rings many meters in diameter. Creosotebush may occasionally sprout from its root crown after disturbance, such as fire.
Soils: Most abundant on alluvial, calcareous, sandy and gravelly soils. Usually does not occupy saline soils.
Associated Species: Bur sagebrush, red brome, yucca, bush muhly.
Uses and Management:
Creosotebush is worthless as forage for livestock and most wildlife. Jackrabbits occasionally eat the leaves, and many small rodents, birds, and reptiles of the desert use it for food and shelter. Onyx, the European antelope, uses it in Southern New Mexico.
Creosotebush invades desert grasslands, and its habitat has increased over 70 times the size it was in the 1930's. This is attributed to decreased fire, heavy grazing, and periodic drought.
Creosotebush may cause dermatitis in humans and animals. Sheep, especially pregnant ewes, have been reported to die after eating the leaves.
American Indians used decoctions as antiseptics, medicines. It has been highly valued for its medicinal properties by desert peoples. It has been used to treat at least 14 illnesses. Twigs and leaves may be boiled as tea, steamed, pounded into a powder, pressed into a poultice, or heated into an infusion. Creosotebush has been reported to be a treatment for malignant melanoma and rheumatoid arthritis.
Creosotebush is host to an insect, Tachardiella larreae, which produces lac and deposits it on the stems of creosotebush. 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, as glue, and for waterproofing baskets.