How to Manage Pests

Identification: Weed Photo Gallery

Jimsonweed

Scientific name: Datura stramonium (Nightshade Family: Solanaceae)

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Jimsonweed is a summer annual broadleaf plant. All of its parts, particularly the seeds, contain alkaloids and when ingested is toxic to humans and livestock. Jimsonweed is found throughout much of California to about 4900 feet (1500 m) except it is generally not found in the deserts, Klamath ranges, and higher regions of the Cascade Range and Sierra Nevada. It inhabits agricultural land and managed or open disturbed places. Leaves have an unpleasant odor when slightly bruised. It is a strong competitor for water and grows rapidly.

Habitat

Fields, pastures, agronomic and vegetable crop lands, orchards, vineyards, ditchbanks, livestock enclosures, roadsides and other open or unmanaged disturbed places.

Seedling

Cotyledons (seed leaves) are long, narrow, lance shaped and expand with age. They can grow 2/5 to 2 inches (10–50 mm) in length. The main stalk below the cotyledons is long, hairy, and usually deep violet. First true leaves are spade shaped with many veins and, at times, appear somewhat puckered. When leaves are crushed they give off an unpleasant odor.

Mature plant

Mature plants grow erect, and reach from 1-3/4 to 4 feet (52.5–120 cm) tall. Stems are coarse, often deep violet, and have branches that are mostly forked. Leaves are football to egg shaped, hairless or nearly hairless, almost 3 to 8 inches (7–20 cm) long, pucker between the veins, and have wavy-toothed to wavy-lobed edges. They are alternate to one another along the stem on stalks that are shorter than the leaf blade.

Flower

Flowers bloom from June through September. The single, showy, white, trumpet-shaped flowers are about 2 to 4 inches (5–10 cm) long, and develop in branch forks.

Fruit

Fruit are egg-shaped pods that are about 1-1/2 to 2 inches (4–5 cm) long, stand erect from the forks of branches, and are covered with many stout spines. When ripe, the pod opens into four separate sections.

Seeds

Seeds are tiny, roughly 1/10 of an inch (0.25 cm), brown to black, semicircular to kidney shaped, and somewhat flattened. Under magnification a wrinkled or pitted surface can be seen.

Reproduction

Reproduce by seed.

Related species/Similar looking plants

Sacred thornapple

More information

• Broadleaf ID illustration
• Calflora's distribution map
• See UC IPM's Pest Management Guidelines for agricultural information