Invasive Plants in Northern Virginia: Mile-a-Minute Weed

By Elaine Mills, Extension Master Gardener

Rampant growth of mile-a-minute weed. Photo © R. S. Chandran, WVU Extension Services.

Persicaria perfoliata (mile-a-minute) is a noxious weed present throughout the Mid-Atlantic and is of serious concern in the Chesapeake Bay watershed. Also known as devil’s tear-thumb, this invasive plant is native to India and Eastern Asia and was accidentally introduced into the United States via contaminated holly seed sent to a nursery in York County, Pennsylvania, in 1930.

An herbaceous annual vine, this member of the buckwheat family gets its name from its vigorous growth; it can extend up to 6 inches a day and grow over 25 feet high within a growing season. Making use of recurved barbs on its thin stems and the undersides of its triangular leaves, it climbs over other herbaceous plants, shrubs, and trees, blocking their access to sunlight and limiting photosynthesis. It can form dense mats in sunny, open and disturbed areas, such as roadsides, fields, forest edges, stream banks, and wetlands.

In addition to its rapid growth, mile-a-minute extends its range via prolific seed production. The plant is self-fertile, not requiring pollinators, and flowers and produces seed from June to October. Its immature green fruits can mature off the vine and produce viable seeds for re-infestation. Seeds in the soil seed bank can remain viable for up to six years.

Mile-a-minute seeds can be carried long distances by birds who eat the berry-like fruits. Mammals — such as chipmunks, squirrels, and deer — also act as vectors, and short-distance dispersal is accomplished by ants which are attracted to the elaiosomes (the nutrient-rich seed coverings). Seeds remain buoyant for seven to nine days, allowing them to spread throughout a watershed, especially during floods. The plant has the potential to move to cooler areas, as its seed requires an eight-week cold period below 50 degrees Fahrenheit for germination.

Dragonfly caught on recurved barb of mile-a-minute weed.
Photo courtesy of University of Maryland Extension.

Manual, mechanical, and cultural control methods can be used to manage this pernicious weed, and there is promising biological management via the mile-a-minute weevil (Rhinoncomimus latipes). Chemical control is more challenging as it is difficult to spray the foliage of the invasive plant without affecting desirable vegetation underneath. For more details, read Mile-a-Minute Vine by (L.) H. Gross from Purdue Extension.


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