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Poisonous Plants: Common Vetch (Vicia sativa)

Common vetch is climbing annual vine brought to North American from southern Europe as a covercrop but has since escaped and become a troublesome weed in shrub and perennial beds in the eastern half of the United States and on the west coast. It likes full sun to partial shade and fertile, moist, well-drained soil, but tolerates less, and can be found in waste areas along roadsides and train tracks, as well as in meadows, abandon fields, croplands and gardens. It grows quickly on the ground or over nearby plants and can weigh them down as it covers them.

Description: The stems of common vetch are weak, trailing, and climbing. They are square in cross-section and can reach 3½ feet in length. Leaves are alternate and pinnately compound, with each of the 3 to 8 leaflets being narrowly oblong, and ¾” to 1½” long. Older leaves develop tendrils that aid in climbing. Pairs of purple to rose and white flowers are produced from spring to late summer in the axis of the leaves on flowering stalks and are 3/4” to 1¼” long. They are followed by flat pods, 1½” to 3″ long, each bearing 3-12 seeds. The root system is deep and fibrous, and bears nodules that take nitrogen from the air and put it in the soil, a benefit of having this plant in your garden.

Poisonous Properties: The significant toxic substances in common vetch are cyanogentic glycosides that release hydrogen cyanide in the presence of enzymes when the vetch is chewed or digested. The concentration of these substances varies with both the strain of the plant and its stage in its life cycle and are especially high in the seeds that can be mistaken for those of garden pea. Cyanide inhibits the oxidative processes of cells which results in cell death. Symptoms of poisoning include headache, tightness in throat and chest, rapid breathing, excitement and restlessness, muscle weakness and in severe cases, convulsions, coma and death. Plants can be detoxified by