Mile-a-Minute Weed

Mile-a-minute weed is one of the invasive species that the State of Maryland currently considers the most troublesome. Learn more below.

Mile-a-Minute Weed
US Government, “Mile-a-Minute Weed,”
October 1, 2010 via Wikimedia Commons,
Creative Commons Attribution.


Mile-a-minute weed is also known as tearthumb. There's a good reason for this: the plants have wicked, razor-like thorns on the back of each leaf and along each stem. The blue-green leaves have a distinctive triangular shape. According to the Plant Conservation Alliance's Mile-a-Minute page, mile-a-minute weeds also have attractive, dark-blue berries.

The Threat

As its name implies, mile-a-minute weed can spread very quickly, overcoming and smothering plants such as tree seedlings. According to the the Plant Conservation Alliance, the plant's seeds are spread mostly by birds. The Alliance also believe that the vines are often spread when berries drop from overhanging branches into flowing streams and creeks beneath them.

Control and Removal

Volunteers who plan to pull mile-a-minute weeds should wear heavy gloves, long pants and long-sleeved shirts. For large infestations, the Plant Conservation Alliance recommends using pre-emergent herbicides early in the spring to prevent the production and distribution of seeds. Because of the water transmission method, it is especially important to control mile-a-minute weed infestations along stream and creek beds.