honey-vine climbing milkweed

Cynanchum laeve is a twining vine with heart-shaped leaves and commonly found in roadsides, fence rows, fields, and disturbed areas. C. laeve is easily recognized as a member of the Apocynaceae by its opposite leaves, milky sap, and distinctive flowers and follicles ("milkweed pods"). The seeds are wind dispersed and can travel long distances. Each plant can produce up to 50 follicles. The root system is fleshy and brittle with a large taproot with other lateral roots, these roots can grow up to 6 feet deep. Developing stems are a light pink and produce a milky sap when broken. Vase-shaped flowers have 5 white petals. These occur in clusters on short stalks. C. laeve flowers from June through September.

Cynanchum laeve occurs in the eastern and central United States and Ontario, Canada. C. laeve can be found in wetland areas in the arid West, Atlantic and Gulf Coastal Plain, Eastern mountain and Piedmont, the Great Plains, Midwest, and the North Central and North Eastern United States. Cynanchum laeve typically lives in disturbed habitats such as thickets, low moist fields, riverbanks, fence rows, and cultivated fields.

Hay fed to livestock can contain C. laeve which can be toxic when consumed in large quantities. Most animals will not eat C. laeve due to its bitter taste. It is recommended by the US Fish and Wildlife Service to take precautionary steps. These steps include not grazing hungry animals in pastures containing C. laeve, eradicating it from driveways and trails, and closely observing livestock that have just been introduced to areas containing C. laeve. C. laeve can be very difficult to eradicate from fields because of its deep, extensive root system. This vine climbs on other plants, and this can cause problems in crop harvesting.

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