Mikania micrantha aka Climbing Hempweed

Mikania micrantha is a vine in the aster family. It is perennial, which means it lives for years. People call it mile-a-minute, bittervine, and Chinese creeper. It is native to much of tropical Central and South America. Its range includes subtropical parts and the Caribbean too. It has spread beyond this range as a serious invasive weed. It threatens crops and wild plants in many warm regions.

The vine has thin stems that twine and branch. The stems seldom exceed 0.07 feet [0.02 metres] in width. They climb over plants or trail across the ground. Its leaves grow in pairs and have a heart shape. Each leaf ends in a sharp tip. The blades range from pale green to yellow-green. Their leaf stalks are green. Leaves reach about 0.42 feet [0.13 metres] long. Growth can reach at least 3 feet [0.91 metres] each week. Tangled stems soon cover open ground. They smother shrubs or small trees.

The flowers are white. In Florida, most bloom comes in November and December. Some bloom lasts into January. Elsewhere, plants can flower and set fruit all year. Florida plants set most seed in December. One plant can produce more than 10,000 seeds. Each seed has a tuft that helps wind carry it. Seeds travel on clothes and animal hair too. Broken stems can take root. Each stem node, or joint, can form roots too.

This vine grows along streams, canals, roads, and forest edges. It invades pastures, plantations, crop fields, and cleared land too. It favors damp air and rich soil with much organic matter. High soil moisture and damp air help it grow well. It can cope with some shade. Growth is poor in heavy shade. These traits help it spread through disturbed ground near forests. Its dense cover blocks light from the plants beneath it.

People have grown it for ground cover and for its looks. These uses risk spreading it beyond its native range. Cutting alone gives poor control, since stem pieces can regrow. Digging plants out takes a lot of work. People also gather it for use in traditional medicine. Reported uses aim to treat stomach pain, fever, and skin problems. These reports do not prove that the treatments work or are safe. Useful Tropical Plants lists no known food uses or hazards. This does not prove that the vine is safe to eat.