Native to the southern United States and northern Mexico, but now introduced to and present in almost all states of the U.S.
A spreading annual weed that has become resistant to many kinds of herbicides, making it more difficult to control when present in agricultural settings. Leaves and stems are covered with sticky hairs and the entire plant has a foul smell when handled or damaged. Reproduction is from seeds produced in a large, hooked seedpod that may attach to passing animals. The dried seed pods are also used in decorative plant arrangements, further contributing to the spread of the seeds and the plants.
Mature plants tend to sprawl due to the heavy stems and foliage, usually remaining under 1.5 feet in height, but spreading to 6 feet in diameter. Stems and leaves are covered with soft hairs that exude a sticky oil, contributing to the foul odor when handled. Mature leaves may be 6 inches across and are heart-shaped, with deep lobes at their base, and they are on stalks up to 6 inches long. Flowers have 6 large petals that are joined at their bases to form a deep tube or funnel, and they occur in small groups at the ends of the stems. They are yellowish-white with dark purple blotches within the circle of the petals and in the tube. The seed pod is a huge, hook shaped beak, with the curved section longer than the rest of the pod. As it matures it darkens, hardens, and splits open to form the 2 curved horns that give it its common names.
Characteristicts Important to Control:
Physical removal of plants where possible effectively eliminates them if done prior to seed production. A non-selective herbicide will kill plants, and pre-emergent control may be possible to some extent.