Jimsonweed (Datura stramonium) is a non-native, annual, herbaceous plant. The plant is found throughout New York and most of the country. Jimsonweed can grow in a variety of habitats but prefers rich soils, thriving in cultivated fields, pastures, barnyards, and wastelands. It is an especially problematic weed in soybean fields due to its competitiveness in high nitrogen soils.
Mature jimsonweed plant. Photo by Lynn Sosnoskie, University of Georgia, via Bugwood.org.
Toxicity
All parts of Jimsonweed are toxic. Jimsonweed toxins impact most domesticated animals including cattle, goats, horses, sheep, swine, and poultry. Typically, leaves and seeds are responsible for poisoning, although their unpleasant odor and taste discourage them from being eaten directly by livestock. Jimsonweed is only grazed if hungry animals are left to graze in sparse, infested pastures. The most common source of poisoning is feed contamination in hay or silage. Additionally, jimsonweed seeds may contaminate grain that is used for feed, which is the most common cause of jimsonweed poisoning in chickens. Jimsonweed is also toxic to humans and surprisingly, poisoning from the plant is more common in humans than livestock. Poisoning in humans is often related to intentional consumption or from eating grain contaminated with jimsonweed seeds. Some symptoms of jimsonweed poisoning include rapid pulse and breathing, polydipsia, depression, diarrhea, low body temperature, convulsions, coma, and in some cases, death. For more detailed information on jimsonweed toxicity please visit Cornell University’s Department of Animal Sciences’ Poisonous Plant Database and Colorado State University’s Guide to Poisonous Plants.
Identification
Seedlings:
Jimsonweed emerges in spring (May through mid-June). Cotyledons (seed leaves) are long, narrow, lance-shaped, and range from 1 to 5 cm (2/5 to 2 inches) in length. The seedling stalk is dark purple and hairy. Subsequent leaves are larger and spade-shaped, with many visible veins. Seedlings will give off an unpleasant smell when crushed.
Jimsonweed seedling. Photo by Bruce Ackley, The Ohio State University, via Bugwood.org.
Young jimsonweed plant. Image by Ohio State Weed Lab , The Ohio State University, via Bugwood.org.
Leaves:
Jimsonweed leaves are 3-8 inches long, hairless and football- to egg-shaped, wavy toothed to lobed along their edges, somewhat resembling red oak leaves. When bruised, leaves give off an unpleasant smell. Leaves are arranged alternately along the stem.
Jimsonweed leaves. Photo by Bruce Ackley, The Ohio State University, via Bugwood.org.
Jimsonweed plants. Image by Joseph M DiTomaso of UC-Davis, via Bugwood.org.
Mature plant:
Jimsonweed plants are branched and upright, up to 5 feet tall at maturity, with densely haired, pale green to purple stems. Root systems are shallow, with a highly branched taproot.
Jimsonweed plant. Image by Howard F Schwartz of Colorado State University, via Bugwood.org.
Jimsonweed stem. Photo by Tom Heutte, USDA Forest Service, via Bugwood.org
Flower/fruit:
Flowers bloom from June through September. Flowers are 204 inches long, white to purple, and trumpet-shaped 2-4 inches long. Often the majority of the flower will be white with a purple center. Jimsonweed’s fruit is a hard, spiny, green, egg-shaped capsule around 2 inches in diameter. As it matures, the fruit turns to a dark brown and splits lengthwise into 4 parts when ripe to release its seeds. Each capsule contains 600 to 700 tiny brown to black seeds.
Jimsonweed flower. Image by Leslie J. Mehrhoff, University of Connecticut, via Bugwood.org.
Jimsonweed seed pod. Image by Leslie J. Mehrhoff, University of Connecticut, via Bugwood.org.
Management
Chemical control
Due to its toxicity, jimsonweed removal is a priority especially in hay fields and grain crops, and in manure and compost storage areas. Please see Cornell’s Crop and Pest Management Management Guidelines, or Cornell University’s Turfgrass and Landscape Weed ID app for guidance.
Non-chemical control
Jimsonweed’s toxicity makes it a priority for control and eradication, especially on grain farms or in hay fields. Jimsonweed can be controlled mechanically, but this must be done before the plant is established to be effective. Seedlings emerge from a lower depth than many other weeds, and can escape rotary hoes and tine weeders; older plants may also be able to regenerate. Seedling burial through hilling or lateral-movement tine weeding can kill small jimsonweed seedlings. Flame weeding and mowing are also effective on small jimsonweed plants.
In fields contaminated with jimsonweed, avoiding overfertilization can minimize jimsonweed growth and choose highly competitive crops. No-till and cover crop residue can reduce jimsonweed emergence. If plants overtop a crop, removing the top of the jimsonweed plant can reduce competition and seed set.
References
Colorado State University, Guide to Poisonous Plants: Jimson-weed https://csuvth.colostate.edu/poisonous_plants/Plants/Details/7
Cornell University, Department of Animal Science, Poisonous Plant Database: Datura spp. http://poisonousplants.ansci.cornell.edu/jimsonweed/jimsonweed.html
Cornell University’s Crop and Pest Mamanagement Guidelines https://cropandpestguides.cce.cornell.edu/
Many of the non-chemical guidance is from Chuck Mohler of Cornell University. Please watch for his upcoming book, Manage Weeds on Your Farm: A Guide to Ecological Strategies.
Cornell University’s Turfgrass and Landscape Weed ID app. Identification and control options for weeds common to turf, agriculture, and gardens in New York; uses a very simple decision tree to identify your weed. http://turfweeds.cals.cornell.edu/plant/control/224
Michigan State University, Department of Plant, Soil and Microbial Sciences, Weeds: Jimsonweed https://www.canr.msu.edu/weeds/extension/jimsonweed
University of California Agriculture & Natural Resources, Statewide Integrated Pest Management Program: Jimsonweed (Datura stramonium) http://ipm.ucanr.edu/PMG/WEEDS/jimsonweed.html
Edler, B. et al. (2015) ‘Growth responses to elevated temperature and reduced soil moisture during early establishment of three annual weeds in four soil types’, Journal of Plant Diseases and Protection, 122(1), pp. 39–48. doi:10.1007/bf03356529.