Larrea tridentata aka Larrea Tridentata

Larrea tridentata, or creosote bush, is an evergreen desert shrub. It belongs to the caltrop family, Zygophyllaceae. Its native range spans the southwestern and south-central United States into Mexico. It grows in the Mojave, Sonoran, and Chihuahuan deserts. Garden plants reach 3–10 feet [0.9–3 metres] tall. Some sources give 4–5 feet [1.2–1.5 metres] as usual. Larger plants can reach 15 feet [4.6 metres]. Growth is slow, with many stems and a rounded or vase-shaped form.

Thin, branching stems rise at an angle from the base. Young bark is smooth and gray. Older bark darkens and forms shallow cracks and flat plates. Slender twigs range from pale gray to reddish brown. Dark rings mark their swollen nodes. Opposite leaves each have two leaflets joined at the base. Their color ranges from yellow-green to dark green. A sticky resin coats the leaves and gives them a strong scent. Rain brings out that scent. Leaves can fold to limit water loss during drought.

Yellow flowers grow singly where leaves meet the stems. Each flower has five petals. Bloom can occur through much of the year, strongest in spring. Flowers also appear in summer and fall. Heavy bloom can give the whole shrub a yellow tint. The small, rounded fruit has a fuzzy coat. Its color ranges from brown to burgundy. It splits into five sections, each holding one seed. The plant spreads through clones around its edges. One colony has an estimated age of about 11,700 years.

Full sun, heat, and good drainage suit this shrub. It grows in sandy, rocky, or lime-rich ground. Oregon State reports broad soil tolerance and tolerance of reflected heat. Dry, shallow soils produce a more open form. More water makes growth denser. Sources place it in USDA zones 7–10. It suits dry gardens, slopes, screens, hedges, and rock walls. It provides cover for small mammals and resists deer. Gall midges can cause galls, though few other problems are reported. Seeds germinate slowly, and cuttings are hard to root.

Indigenous peoples have used this plant as medicine. Recorded food uses include pickled buds and leaf or stem tea. These uses do not establish safety. Swallowing it has been linked to serious liver inflammation. Skin contact can cause dermatitis. PFAF does not consider it safe as an herbal remedy. ASPCA lists it as non-toxic to dogs, cats, and horses.