General: Creosote bush (Larrea tridentata) is one of the signature plants of the southwestern deserts. Creosote bush is the dominant species in the Lower Sonoran (Creosote-Bursage Flats) life zone, a major component of the Upper Sonoran (Mojave Desert Scrub) life zone, and fades out at the bottom of the Upper Sonoran (Pinyon-Juniper Woodland) life zone.

Family: Caltrop (Zygophyllaceae).

Other Names: Creosotebush, little stinker.

Plant Form: Evergreen shrub with many branches emerging from the ground and radiating up and outward. The plant can drop some or most of the leaves during drought.

Height: Height depends on precipitation. Typical plants get to 5-6 feet tall. In dry areas such as the west side of the Sheep Range (rain shadow of the Spring Mountains), plants rarely exceed about 3 feet. In well-watered areas, plants can exceed 10 feet.

Stems: Generally crooked and divided; young stems are banded.

Leaves: Small (less than 0.5 inches), waxy, and resinous. Two leaflets are joined at the base. The leaf color depends on season (water): leaves are dark green to yellowish green during spring when water is available, but they turn brown during summer or when water is not available.

Flowers: Petals 5, solitary, about 1-inch across at most, and yellow. The plant blooms when water is available, usually in the spring after winter rains and during summer after thunderstorms.

Seeds: Round, fuzzy, white capsule about 0.25 inches in diameter.

Elevation: Up to about 4,500 ft.

Comments: Creosote bushes are thought to include the oldest individual plants on earth. This species grows from seeds and by cloning, and some clones in southern California have been carbon dated to about 11,000 year old.

This species gives the desert a characteristic musky odor after summer rains. After summer thunderstorms (localized, heavy rain storms), you can see patches or bands of bright green creosote bush stretching out across the landscape where it rained, while the surrounding landscape remains brown.