- Pest Type: Weed
- Crops Affected: Wheat, Cotton, Potatoes, Soybeans, Corn
- Scientific Name: Datura stramonium
- Pest Order: Solanaceae
Jimsonweed is a large summer annual with erect branching stems (0.3-2 m tall) and distinctive egg-shaped seed capsules covered with prickles. The foliage has a strong unpleasant odor. Jimsonweed is toxic to all classes of livestock and to humans. All parts of the plant are poisonous, but toxic effects on humans usually occur after seeds are ingested. Plants contain tropane alkaloids, of which most notable are atropine, hyoscyamine, and scopolamine.
Reproduction is by seeds. Seeds germinate from late spring through summer, if adequate moisture is available. Seeds are kidney-shaped, flattened, pitted and wrinkled, dark brown to black and about 3 mm long.
Hypocotyls are maroon and hairy. Cotyledons are thick, smooth, lanceloate (about 5 cm long by 6 cm wide). Petioles of the cotyledons are hairy on the upper surface. The seed coat is attached to the cotyledons long after germination. Leaves are alternate. First leaves are entire; subsequent leaves have a few irregular teeth. Seedlings emit a strong unpleasant odor.
Stems are smooth, green or purple, with inconspicuous hairs. Leaves are alternate.
Stems remain smooth and green or purple. Leaves are large (7-20 cm long), on stout petioles, oval to ovate, smooth, dark green above. Leaf margins resemble those of oak leaves, coarsely and unevenly toothed.
Jimsonweed plants have a thick, shallow, and extensively branched taproot.
Flowers are produced from early summer until frost and open in late afternoon and evening. White to purple flowers are large and conspicuous, funnel-shaped, 5-12.5 cm long, arising from short stalks/pedicels solitary in the branch axils. Sepals are strongly 5-ridged, 5-toothed, and enclose the lower part of the floral tube. Petals are fused into a 5-lobed floral tube. Fruit capsules are 3-5 cm long, green when immature, egg-shaped, 4-celled, and covered with stiff prickles. Mature capsules are brown and hard, splitting into 4 segments, each containing several seeds.
Leafless stems persist after death, bearing the distinctive spiny 4-parted seed capsules. Sepals form a skirt-like structure at the base of the capsule.
This is a weed of most agronomic, horticultural, and nursery crops. It is found on most soil types but prefers nutrient-rich soils. Old-fashioned hog lots almost always have some jimsonweeds.
Jimsonweed can be found in most states of the United States except for the Pacific Northwest and northern Great Plains. It is most common in the southern US. It can also be found in southeastern Canada and in Mexico.
In the seedling stage, common cocklebur looks similar, but cocklebur seedlings have larger cotyledons and the young leaves of cockleur are not smooth and have more pronounced teeth on the margin. Cocklebur also lacks the distinctive odor of jimsonweed.