Datura stramonium is a flowering plant native to certain tropical and subtropical regions in the Americas as well as some Old World tropics and subtropics. It is an invasive alien species in the North American and other temperate zones, producing considerable damage to crops. Herbicidal control of this weedy species is often undertaken by use of the triazinone herbicide Metribuzin.
Known by a common name of Jimsonweed, this broadleaf annual erect herb manifests as a shrub up to 150 cm high. The toothed leaves are soft and irregularly undulate, while the creamy white fragrant flowers are trumpet-shaped; flowers sometimes range to a violet hue and may extend to a length of approximately 90 millimeters. These flowers usually do not open fully. The ovate seed capsule is approximately three cm in length and is sometimes spine covered.
The common name 'Jimsonweed' is probably a corruption of 'Jamestown Weed,' referring to where this species was first observed in North America. Another common name that is often used for this species is 'Thornapple.' Two varieties of Jimsonweed have been described. The typical variety has green stems and white flowers, while var. tatula has purple stems and either pale violet or purple-striped flowers. Jimsonweed has a distinct appearance, making it easy to identify.
This adventive plant is a summer annual about 3-5' tall that branches dichotomously. The stems are green or purple and largely hairless, although young stems often have conspicuous hairs. The alternate leaves are up to 8" long and 6" across (excluding the petioles). They are ovate or ovate-cordate in outline, but pinnately lobed. These lobes are somewhat shallow and pointed at their tips; there are usually 2-3 of these lobes on each side of the leaf blade. The margin of each leaf may have a few secondary lobes or coarse dentate teeth, otherwise it is smooth or slightly undulate. The leaves may be slightly pubescent when young, but become hairless with age; the upper surface of each leaf is often dark green and dull. The foliage of Jimsonweed exudes a bitter rank odor. Individual flowers occur where the stems branch dichotomously; the upper stems also terminate in individual flowers. The funnelform corolla of each flower is up to 5" long and 2" across when fully open; its outer rim has 5 shallow lobes. Each of these lobes forms an acute point in the middle.The corolla is white or pale violet throughout, except at the throat of the flower, where thick veins of dark violet occur. The light green calyx is shorter than the corolla and conspicuously divided along its length by 5 membranous wings. The blooming period occurs from mid-summer to early fall and lasts about 2 months. The flowers usually don't open up until midnight and close early in the morning; less often, the flowers may bloom toward the middle of the day, especially when it is cloudy. Individual flowers last only a single day. Each flower is replaced by a hard fruit that is dry and spiny; it is about 1½" long, 1" across, and spheroid-ovoid in shape. Underneath each fruit is a truncated remnant of the calyx that curves sharply downward. These fruits are initially green, but become brown with maturity; they divide into 4 segments to release the seeds. The large seeds are dull, irregular, and dark-colored; their surface may be pitted or slightly reticulated. The root system consists of taproot that is shallow for the size of the plant; it branches frequently. Jimsonweed spreads by reseeding itself. Cultivation
Herbs or subshrubs, sometimes robust, 0.5-1.5 m tall, glabrescent. Petiole 3-5.5 cm; leaf blade broadly ovate, 8-17 × 4-14 cm, membranous, glabrescent, base asymmetric, cuneate, irregularly sinuous or dentate-lobed, apex acuminate, veins 3-5 pairs. Flowers erect. Pedicel 5-12 mm. Calyx tubular, 5-angular, 3-5 cm. Corolla white or pale purple, greenish at base, sometimes purple distally, funnelform; limb 3-5 cm in diam.; lobes 6-10 cm, mucronate at apex. Filaments ca. 3 cm; anthers 3-4 mm. Capsules erect, globose or ovoid, 3-4.5 × 2-4 cm, with copious prickles, rarely smooth, dehiscent by 4 equal valves, subtended by remnants of persistent calyx. Seeds black, ovate or discoid, ca. 4 mm in diam. Fl. Jun-Oct, fr. Jul-Nov.
"Plant 60-120 cm or more tall, branched, pubescent; the branches often purplish. Leaves 8-17 x 4-13 cm, ovate or broadly so, sinuately dentate, minutely puberulose, cuneate. Petiole 2-5 cm long. Calyx 3.5-5.5 cm long, tubular, 5-dentate, puberulous, persistent. Lobes 6-9 mm long, strongly reflexed in fruit, apiculate. Corolla 7-10 cm long, white or purplish suffused; limb up to 8 cm broad, shallowly 5-lobed, with the lobes, ± triangular-acuminate. Anthers ± 5 mm long, with the lobes narrow oblong, usually white. Capsule erect, 3-4 cm long, ovoid, spiny and densely pubescent, splitting by 4 valves; spines up to 5 mm long. Seeds 3 mm long, reniform, reticulate-foveolate, and black."