Invasive Species Watch – Mile-a-Minute Vine
Preventing the establishment of new invasive species is priority number one and the best expenditure of limited resources in an invasive species management program. Next in priority is early detection of and rapid response (EDRR) to the first report of a new invasion. Mile-a-minute vine (Persicaria perfoliata (L.) H. Gross) is native to East Asia. It is a member of the buckwheat family, Polygonaceae. Although its common name exaggerates its growth potential, this annual vine can grow as much as 6 inches a day and can reach heights of more than 25 feet within the growing season. It forms very dense, tangled mats, growing over shrubs, small trees and up the sides of forest edges (Fig. 1). The leaves are simple, alternate, light green and a nearly perfect triangle shape (Fig. 2). The delicately narrow, green to red-tinted stems, and the petiole (leaf stem) and midrib on the underside of the leaves are armed with small, stiff, recurved barbs (Fig. 3). Small, cup- or saucer-shaped leaf structures, called ocreae, encircle the stem at each node (Fig. 4). Clusters of small white, rather inconspicuous, flowers emerge from the ocreae. Flowers develop into clusters of deep, iridescent blue berry-like fruits, approximately 5 mm in diameter (Fig. 4), each fruit containing a single black or reddish-black
hard seed, called an achene. Seeds are dispersed by birds
and mammals, including chipmunks, squirrels and deer, which eat the fruit. Floodwaters facilitate long distance dispersal of seed.
Figure 1 Photo Credit: USDA APHIS PPQ, Bugwood.org
Figure 2 Photo Credit: Leslie J. Mehrhoff, University of Connecticut, Bugwood.orgDistribution: Mile-a-minute vine was found in Indiana for the first time this spring. In May 2018, a single vine was found in Monroe County and verified by experts. No other plants have been found at this time. The nearest documented infestations to Indiana occur in southeast Ohio counties bordering the Ohio River. Because it has not yet arrived in Indiana, and because of the very real threat of its spreading down the Ohio River or being inadvertently introduced into the state by human activity, this invasive vine is listed as a high-priority species for prevention, early detection and rapid response efforts.
Impact: Mile-a-minute’s rapid growth and dense infestations, along with its very early spring germination, gives this species a very substantial competitive advantage over most native plant species. It easily overwhelms, shades out and displaces many native plant herbaceous species. It can overtop, shade out, weigh down, and even break taller herbaceous plants, woody shrubs, and tree seedlings and saplings. Mile-a-minute infestations reduce plant species diversity and disrupt wildlife habitat. Where timber harvesting occurs, mile-a-minute destroys tree seedlings and saplings, resulting in forest regeneration failures.
Figure 3 Photo Credit: Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Figure 4 Photo Credit: Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Numerous invasive vine species with aggressive growth behavior vex forestry and natural resource professionals and landowners. Mile-a-minute vine promises to outdo all of them. Please be on the lookout for this invasive species and report it on EDDMapS (Early Detection & Distribution Mapping System) www.eddmaps.org/indiana/ or from your smart phone on the GLEDN (Great Lakes Early Detection Network) app. If you are unsure if you are correctly identifying a very aggressive vine with characteristics that appear similar to those shown in this article, please contact a forester or other natural resource professional for confirmation or just report it in EDDMapS or the GLEDN app, along with photos, and a professional in your area will verify its identification before it actually gets posted.
For more information on mile-a-minute vine, see Purdue University Cooperative Extension publication FNR-481-W, Invasive Plant Series, Mile-a-Minute Vine (www.extension.purdue.edu/extmedia/fnr/fnr-481-w.pdf).
Ron Rathfon is an Extension Forester with Purdue University. His extension activities are directed to private landowners, professional foresters and other natural resource professionals, youth groups, educators, and the public. In addition, he manages over 600 acres of departmental forest at SIPAC where much of his research is conducted.