July/August 2010

The leaves of the Mile-a-Minute Vine have a shape similar to an equilateral triangular.
Todd L. Mervosh, CAES

Wanted Dead or Alive: Mile-a-Minute Vine

By Will Rowlands

The Connecticut Invasive Plant Working Group (CIPWG) wants your help in tracking down Mile-a-Minute Vine (MAM), an invasive that is spreading north and east across Connecticut. CIPWG is a joint effort that includes scientists and staff from the University of Connecticut (UConn) and the Connecticut Department of Environmental Protection (DEP).

The vine, an annual herbaceous weed that reproduces by seed, has also been spotted in Massachusetts, New York and Rhode Island. The seeds are spread naturally by water and by birds, small mammals and deer that eat the fruit. It can also spread via nursery stock, compost, topsoil and even mulch. Once the vine has fruited, lawn services that mow it could spread seeds to other locations.

The scientific name of the green invader is Persicaria perfoliata .

According to a press release from the state DEP it "outcompetes and overgrows native species, interferes with forest regeneration, disrupts normal ecosystem functioning and can smother and shade out small seedlings of other species."

It climbs over and around other vegetation and trees, weighing them down and hogging sunlight in the process.

The weed is often found along the edges of roads, forests and streams, as well as in meadows and some woodlands, but will also grow in open areas such as abandoned fields, logged forests, forest clearings and utility rights of way. It likes sun but will tolerate partial shade. In shade the plants are smaller.

It got its nickname, "Kudzu of the North," because it can grow as much as 6 inches a day. Branched stems of the weed may reach lengths of 20 feet or more. The vine can also climb poles. You can contact your power company if you see it on telephone poles or wires.

In residential environments, the vine can use hedges as a support system for years before killing them.

First discovered in Connecticut in Greenwich in 2000, MAM has since spread to 17 other municipalities in Connecticut: Bridgewater, Danbury, Fairfield, Lyme, Monroe, New Milford, Newtown, North Haven, Norwalk, Redding, Roxbury, Simsbury, Stamford, Stonington, Torrington, Weston and Westport.

While mainly in Fairfield and Litchfield Counties, the weed has been spotted in Lyme, North Haven, Simsbury and Stonington. Mile-a-Minute Vine has been reported in five of Connecticut's eight counties.

It has been estimated that invasive species cost the U.S. economy $120 billion per year. Mile-a-Minute Vine can threaten farms, orchards, gardens, Christmas Tree farms, reforestation projects, landscaping, and horticultural and nursery crops that aren't tilled on a regular basis. For these reasons, the state of Connecticut has banned the cultivation, transportation, sale or distribution of the species.

Unfortunately, it's still spreading and that's why CIPWG needs your help. Input from the public will identify local populations and help state agencies formulate plans.

MAM is characterized by leaves that are similar in shape to an equilateral triangle, small barbs on the stem, ocrea (saucer-shaped leaves that encircle the stem at nodes) and fruit that turns from green to blue. It is sometimes called Devil's Tail because of the shape of its leaves.

Misidentification is an issue. There are plants that share similarities but MAM has triangular leaves, barbed stems and ocrea. If you see a vine with all three of these characteristics, contact Logan Senack, Connecticut Invasive Plant Coordinator, at 860.208.3900 or mileaminute@uconn.edu . You can also visit www.hort.uconn.edu/mam and select "Report MAM." The site also has photos and tips on identification and control.

Mad Gardeners, a regional association of more than 500 professional and amateur gardeners has been involved in the MAM effort for some time. You can report sightings to Kathleen Nelson at knelson151@sbcglobal.net . If you'd like to volunteer or make a donation to support their work, call Nelson at 860.355.1547. For more information, visit www.madgardeners.com

According to Mad Gardeners, the "stems are often reddish in color and may catch the eye in the fall after leaves are killed by frost."

They also note that MAM has a distinctive color that people can perceive differently, "They all seem to agree on pale, but some say blue-green, others yellow-green."

You can sometimes spot MAM by its die-back which can look like small mounds or clumps. It can also leave a spidery network of branches on plants that it has climbed over.

If the vine is not extensive, you can mow it, cut it or pull it yourself. The earlier you do this the better. Wear gloves (because of the barbs and spines) if you are going to handle the plant, and bear in mind that the plant spreads via seeds. You can compost it only until fruiting.

Vigilance is required as the seeds can survive in soil for up to seven years. Seedlings come up in late April and early May. The plant usually fruits somewhere between mid-July and early August but the exact timing can be affected by seasonal variations.

Plants with fruit should not be left on site, composted or dragged around but rather bagged in place. Donna Ellis, senior extension educator in the Department of Plant Science at the UConn College of Agriculture & Natural Resources and co-chairman of CIPWG, recommends solarizing. To solarize, place the MAM in sealed black plastic bags and let them bake in the sun for at least a week or two (more if it isn't sunny) before disposing.

Pre- and/or post-emergence herbicides are an option if the MAM is extensive. If you choose that approach, it's important to use one appropriate for MAM and to follow directions. Consult a licensed herbicide applicator before applying herbicides over large areas.

Ellis notes that Connecticut municipalities have differing regulations regarding the disposal of invasive plants. It's an evolving issue as more people become aware of invasives and related issues. She said the Connecticut Invasive Plant Council (CIPC), a nine-member commission, is looking into the matter.

The weed has recently been reclassified so you may see it under its old scientific name, Polygonum perfoliatum . It is also sometimes called Devil's Tearthumb.

MAM is native to India and Eastern Asia. It is widely accepted that the weed first arrived in the U.S. in Portland, Ore., in the 1890s in ship ballast. According to Ellis, it arrived on the East Coast in Pennsylvania in the 1930s as hitchhiker seeds in nursery stock.

Biological control with nonindigenous weevils has had success in other states. Tests indicate that the weevil, Rhinoncomimus latipes, is host specific to the vine and poses no significant threat to fauna or flora in our area.

Adult weevils eat the leaves and lay eggs on leaves and stems. The larvae bore into the stem and eat from the inside which can stunt growth, inhibit seed production or even kill the vine.

The weevils, which are small and native to northeastern, central and southern China, have been released in Bridgewater, Greenwich, New Milford, Newtown and North Haven. This spring, the weevils were released in Fairfield, Stamford and Westport. Carole Cheah, a research entomologist with the Connecticut Agricultural Experiment Station's Valley Laboratory told us that some of the weevils released last year survived the winter.

Residents seeking assistance should contact the Connecticut Invasive Plant Working Group ( www.hort.uconn.edu/cipwg ), the Connecticut Agricultural Experiment Station ( www.ct.gov/CAES/ ), or the state DEP ( www.ct.gov/dep/ ).

Information available from UConn, CIPWG, Connecticut DEP, the Invasive Plant Atlas of New England (IPANE), Mad Gardeners and the USDA was indispensable in compiling this report.

Mile-a-Minute Vine in Connecticut, updated May 2010.
Kristen Ponak, UConn

Mile-a-Minute Vine has small barbs on its stems and bears fruit that turn from green to blue. Do not compost the plant once it has fruited.
Todd L. Mervosh, CAES

Mile-a-Minute Vine has ocrea, saucer-shaped leaves that encircle the stem at nodes.
Les Mehrhoff, IPANE

Will Rowlands releasing weevils in Westport. Note the clump of die-back in the foreground.
Donna Ellis, UConn