Derecho Comparado

Description

Mile-a-minute grows as an annual vine, climbing up to 20 feet in height (Mountain 1989). Its rapid growth--up to a half a foot per day-- accounts for its common name. The leaves are bright green and triangular, from 1-3 inches wide. Both the leaves and stems have short spines and prickles. The pea-size fruits are blue in color, and mature in late summer. The seeds are dispersed by birds, rodents, and water. It can be distinguished from other species of

Polygonum by its triangle-shaped leaves and the flaring, saucer-shaped sheath at the base of each

leaf (Virginia NHP 1998). Habitat

In New Jersey, mile-a-minute has been collected from dredge spoil (see specimen citation below) and from damp soil at the edge of wooded thickets, old fields, meadows, forest edges, and railroad and highway right-of-ways (D. Snyder, private herbarium). The species can climb to heights of 15 feet or more (D. Snyder, personal observation. Typical habitats in adjacent Pennsylvania also include nurseries, reforestation clear-cuts, utility right-of-ways, meadows and stream banks (Mountain 1989). Mile-a-minute establishes quickly on damp disturbed ground where there is plenty of sun, but it also grows in shadier habitats where the leaf litter keeps the ground damp. In Gloucester County, New Jersey, the species has been observed flowering and fruiting in full shade of a closed canopy red maple-black gum forest (D. Snyder, personal observation).

Distribution

Indigenous to Japan, mile-a-minute was introduced accidentally into Pennsylvania in the 1940’s, apparently as a contaminant in imported holly seeds and its subsequent spread may be, at least in part, as a soil contaminant in nursery grown rhododendrons (Hickman and Hickman 1978; Rhoads 1999). It has spread north into New York State, west to Ohio, and south to North Carolina (Kartesz 1999). There are apparently disjunct occurrences reported from Mississippi, Oregon, and British Columbia, Canada (Kartesz 1999; USDA 1998). It is considered invasive in Delaware, Maryland, New York, North Carolina, Ohio, Pennsylvania, and Virginia. In New Jersey, the only collections seen were from Salem (see specimen cited below) and Gloucester, Mercer, and Monmouth counties (D. Snyder, private herbarium). It has recently been reported from Union County (Misseck 2000) and there are unvouchered reports from Burlington County (Wycoff 1998), Bergen County (K. Anderson, pers. comm.), and from several locations in central New Jersey (F. Yoder, pers. comm.). At present, the species reaches its greatest abundance in the Delaware River valley in Gloucester and Salem counties where some infestations occupy an acre or more of old field habitat.

Threats

The rapid and dense growth of mile-a-minute allows it to overtake native vegetation, smothering seedlings and outcompeting mature plants (Virginia NHP 1998; USDA 1992). Large infestations significantly alter the structure of natural plant communities and ultimately reduce biodiversity. Within the last decade, mile-a-minute has rapidly become a significant pest in several locations along the Delaware River in Gloucester and Salem counties (D. Snyder, personal observation) and in the Watchung Reservation, Union County (Misseck 2000). It is of particular concern in wet meadows that may harbor rare wetland plants (Virginia NHP 1998). A Gloucester County population of the state listed endangered Lancaster sedge (Cyperus

lancastriensis) was destroyed within the span of a decade when its habitat was overrun and

smothered by mile-a-minute (D. Snyder, personal observation). It is also weed of gardens and landscaped yards. It has the potential to become a serious pest in agricultural lands (D. Snyder, personal observation).

Control

Mile-a-minute can be hand-pulled (wearing gloves) from small areas before they set seed, and before they grow so much as to overtake other vegetation (Virginia NHP 1998). The plants lack deep-seated roots and are fairly easy to pull. Mowing or weed whacking is effective as long as it is done prior to fruiting (Mountain 1989). Removing thick litter layers may also help to control the spread of the plant. Heavily infested areas can be treated with herbicides before the plants go to seed. Herbicides should be used with caution as they can harm co-occurring indigenous plants. Research on a biological control agent (a beetle, Rhinoncomimus latipes) is underway at the University of Delaware (L. Morse, pers. comm.). Because mile-a-minute is apparently not yet widespread in New Jersey, successful control may be relatively easily achieved if aggressively pursued.

Literature Cited and Other Sources of Information

Anderson, K. 1992. Two new adventives for New Jersey. Bartonia 57: 104-105. EarthBase. 1995. Invasive weed alert – North East. EarthBase, Inc. Available online:

www.earthbase.org/home/essays/docs/mileamin.

Kartesz, J.T. 1999. A Synonymized Checklist and Atlas with Biological Attributes for the Vascular Flora of the United States, Canada, and Greenland. First Edition. In Kartesz, J.T., and C.A. Meacham. Synthesis of the North American Flora, Version 1.0. North Carolina Botanical Garden, Chapel Hill.

Hickman, I.C. and C.S. Hickman. 1978. Polygonum perfoliatum: a recent Asiatic adventive. Bartonia 45: 18-23.

Mountain, W.L. 1989. Mile-a-minute (Polygonum perfoliatum L.) update—distribution, biology, and control suggestions. Regulatory Horticulture Weed Circular 15: 21-24. Bureau of Plant Industry, PA Department of Agriculture.

Oliver, J.D. 1996. Mile-a-minute weed (Polygonum perfoliatum L.), an invasive vine in natural and disturbed areas. Castanea 61: 244-251.

Rhoads, A.F. 1999. Invasive exotic plant species in the Pennsylvania flora. Available online at

http://tncweeds.ucdavis.edu/paconf/conf14.html.

United States Department of Agriculture. 1998. Polygonum perfoliatum. Natural Resources Conservation Service. Available online:

http://plants.usda.gov/plants/fr_enter.cgi?earl=fr_qurymenu.

United States Department of Agriculture Forest Service. 1992. Pest alert – Mile-a-minute. U.S. Government Printing Office NA-PR-04-91.

Virginia Natural Heritage Program. 1998. Fact Sheet – Mile-a-minute. Available online:

http://www.state.va.us/~dcr/dnh/invpoly.htm.

Wyckoff, P.L. 1998. State grids for invasion by thorny mile-a-minute plant. The Star-ledger, July 17.

Representative New Jersey Specimens Examined

Salem Co.: Along access road to spoil banks, W of Rt. 130 and S of Rt. 602, Oldman’s Twp., 27 September 1991, J. Courtney s.n., PH.