History & Introduction

Mile-a-minute,  also known as Persicaria perfoliata, is a fast-growing, barbed vine from the Buckwheat family that gets its name from its ability to grow up to 6 inches per day. Currently, it is estimated that mile-a-minute grows in about 20% of its potential U.S. range and can potentially expand to cooler areas as the seeds only require about a two-month cold period to flower. This vine is considered a threat to native vegetation and habitats in natural areas, as well as reforestation areas and young forest stands.

Mile-a-minute, is native to Eastern Asia, India, and the Philippines, including the islands from Japan to the Philippines. Its native range also includes Nepal, Burma, Manchuria, China, Korea, Taiwan, and the Malay Peninsula.

In the United States, mile-a-minute was experimentally introduced into Portland, Oregon in 1890, and in 1937 to Beltsville, Maryland, but did not become established at either site. An additional, yet unintentional, introduction occurred (via contaminated holly seedstock) in the 1930s to a nursery site in York County, Pennsylvania. Unfortunately, this introduction was successful. The plant was allowed to reproduce, and is the likely source of this invasive plant in the mid-Atlantic and northeastern United States. It is possible that the plant may have been further spread by contaminated nursery stock leaving this York County nursery as well. 

In the past 90 years, the range for this plant in the United States has expanded more than 300 miles from the York County site. In New York State (NYS), according to the NYS Regulation 6 NYCRR Part 575 list of Prohibited and Regulated Invasive Species, the plant is prohibited in New York State. Prohibited invasive species cannot be knowingly possessed with the intent to sell, import, purchase, transport, propagate or introduce. 

The Long Island Invasive Species Management Area (LIISMA) is one of the eight PRISMs, or Partnership(s) for Regional Invasive Species Management in New York State, that work together to prevent or minimize the harm caused by invasive species in New York’s natural areas and environment. According to the New York Natural Heritage Program’s (NYNHP) NYS Invasive Species Tier List, mile-a-minute is ranked as a Tier 4 (local control) in the state and in LIISMA PRISM. Tier 4 species are species categorized in that eradication from the PRISM is not feasible. Instead, the PRISM may focus on localized management over time to contain, exclude, or suppress the species to protect high-priority resources like rare and endangered species, or recreational assets. 

Identification & Biology

Mile-a-minute is an herbaceous, annual vine that invades disturbed areas in Oregon and portions of the northeastern and mid-Atlantic United States. This species grows best in full sun, but will tolerate partial shade, and prefers sites with moderate to high soil moisture. The ongoing fragmentation of forested land due to development is creating more habitat opportunities for the establishment of this species.

The vine has narrow, angular, delicate, reddish green stems, is highly branched, and covered with small, recurved spines over the stems, flowers, and underside of leaf stalks. These barbs become sharper as the plant matures and help support the plant’s vertical climb. 

This troublesome vine has alternate leaves; shaped like an equilateral triangle with a somewhat heart-shaped base when immature. The leaves are one inch wide at their widest point, vibrant green, and barbed on the underside. Leaf-like, saucer-shaped ocrea encircle the main stem at the base of each leaf petiole.

The flowers are inconspicuous, pale green, and clustered on short stems that originate from above the ocrea area. Flower production continues until frost. The seed requires an eight-week cold period in order to produce flowers. 

The plant has a fleshy, berry-like fruit produced from early summer until frost; fruit emerges green, changes to purple, then matures to a striking metallic blue. The fruit measures about 0.25 inches across and appears in a long cluster at the vine’s tips, above the ocrea area. The fruit is also segmented, with each segment containing a single, small, glossy black or reddish-black seed. Fruit can remain buoyant for up to nine days in water.

Mile-a-minute reproduces by seed, which can remain viable in the seed bank for at least six years, making eradication difficult. Seeds germinate in early April. The fruit is consumed and seeds are distributed by birds, deer, and small mammals. Seeds can also be transported in contaminated soil found on heavy machinery and logging equipment. Seeds also transport by way of wind, water movement, and human disturbance, and are dispersed in soil or water in riparian and wetland areas. 

Damage & Concern

Mile-a-minute has been reported as invasive in natural areas from New Hampshire to North Carolina—with Pennsylvania as the epicenter—and in Ohio, Indiana, Iowa and Oregon. Sources report the species establishing on a wide range of sites, and seems to establish best in areas with high light and moisture, and abundant plant litter. 

Mile-a-minute is an early successional species that establishes most readily in disturbed areas, particularly those associated with human activity. These include roadsides, railroad tracks, ditches, nurseries and orchards, powerline rights-of-way, hedgerows, recreational areas, open fields and any open, disturbed areas. The plant also establishes along forest edges, in openings in forested areas, on eroded banks, and in thickets, gullies, and meadows. Mile-a-minute is widely known to be a rapid colonizer of wetlands and streambanks. 

The vine’s rapid growth allows it to climb and sprawl densely over other plants up to 20-30 ft., thus restricting light availability, smothering existing native plant vegetation and potentially eliminating plants below. Dead stems persist through winter, forming a tangled, interwoven mass over desirable vegetation.

Management & Control

Safety is a key consideration when working with this plant. Long-sleeved shirts and leather gloves should be worn as protection from the plant’s sharp barbs. Barbs harden as the plant matures. Once a site populated with mile-a-minute vines has been cleared, the site should be replanted with native species to reduce or prevent regrowth. It is important to monitor for new seedlings that may emerge.

Prevention 

The most cost-efficient and effective method of managing invasive species is to prevent their establishment and spread in the first place by maintaining healthy natural communities and by conducting monitoring of newly emerging invasive species several times each year. Managing to maintain the integrity of the native plant community and mitigate the factors enhancing ecosystem disturbances is likely to be more effective than managing solely to control any particular invasive species. 

Cultural control

Similar to prevention measures, cultural methods of  mile-a-minute control include supporting the integrity of existing plant communities, such as maintaining wide streamside forest buffers in riparian areas and stable vegetative cover in upland areas

Mechanical Control

Hand-pulling and mowing can be effective. Hand-pulling is the most practical approach for small populations. It is recommended to start pulling vines once they are easy to see. The plant’s rapid growth rate quickly produces large quantities of vegetative material and subsequent flowers and fruit, if plants are allowed to grow without frequent pulling. Plants should be pulled every three weeks from mid-May or early-June until the  first frost. It is critical that plants are pulled before seeds are produced, which can begin as early as mid-June and can continue on until September to November. 

Due to the plant’s annual habit, manual removal can be fairly effective as long as repeated efforts are implemented to reduce the seedbank. Reduction of the seedbank will require at least 3-5 years of consistent effort and monitoring for new seedlings, and this process should continue indefinitely. Repeated cutting to ground level (with shears, hedge trimmers, hand pruners or a mower) will keep growth confined and prevent fruit set, which may reduce localized seed development. If seeds are present, inspect and thoroughly clean equipment after use to avoid seed dispersal to new locations.

Disposal of Plant Material

Before June, when fruit is not yet evident, removed mile-a-minute plant material can be left on site to dry and decompose. After flowering begins, pulled plants should be bagged and destroyed. NOTE: After removal, green fruit may continue to ripen on extracted vines. Immature seeds can still germinate. Fruit and seeds should not be composted.

Chemical Control

In areas with large mile-a-minute populations, or where location or access makes hand-pulling or mowing difficult, chemical control (pre- or post-emergent herbicide) may be a viable option. Commonly used herbicides can be used in moderation, however, this may be an undesirable method, as spraying herbicide can damage the natural vegetation that is being overtopped by this invasive vine. Location of the infestation will dictate the product type and the scope of the treatment needed. Consult with a licensed pesticide applicator. Always be sure to follow all label directions when using all chemical treatments.  Refer to Penn State Extension’s Management Calendar , CIPWG’s Invasive Plant Management Calendar or Penn State Extension’s Management Calendar and section for treatment and timing of mile-a-minute control for more information.

Biological Control

As of 2004, the beneficial mile-a-minute weevil (Rhinoncomimus latipes), host-specific to mile-a-minute vine and a native of China, was approved by the USDA for biocontrol of the species. Adult weevils feed on foliage, while larvae feed within stems at nodes. Adult weevils lay their eggs in the leaves, stems, and buds of the plant, where larvae feed until they pupate and drop into the soil. The insect’s life cycle spans about one month, with several generations taking place over one growing season.

Damage from these weevils may cause enough damage to limit seed production in the plant. In some areas, populations have completely collapsed 1 to 2 years following introduction of mile-a-minute weevils. Scientists from the University of Connecticut and The Connecticut Agricultural Experiment Station introduced approximately 18,000 weevils in 10 Connecticut towns for biological control of this invasive vine beginning in 2009, with much success. The weevils are established at each release site and over time have provided a sustainable solution to reduce mile-a-minute populations in the state.

Monitoring & Reporting 

LIISMA is monitoring mile-a-minute in priority conservation areas. As reports of the species are collected, LIISMA works with partners and landowners to delineate and manage early emerging infestations of the species before they become widespread. Mile-a-minute is currently a Tier 4 species on Long Island, prioritized for local control as needed.

Your reports matter to us–report the species to iMapinvasives or iNaturalist as soon as you detect it!

iNaturalist is an app and website that can help you record your own observations, identify species, collaborate with others, and access the observational data collected by iNaturalist users. Already using iNaturalist? Join a LIISMA iNaturalist Project to have your invasive species observations automatically uploaded to our projects! Here are some of our projects you can join: Invasive Species in Priority Areas, EDRR Species, LIFERS, Tier 1 Invasive Species, and more!

Want to dive deeper? Check out iMapInvasives to map invasive species like a pro!