Fall - Mile-a-minute vine
Mile-a-minute vine or Mile-a-minute weed (Persicaria perfoliata)
This annual plant gets its nickname from its rapid growth (up to 6 inches in a single day). A native of Asia, it arrived in Pennsylvania, probably in a shipment of holly seeds, in the 1930’s. Since then, it has spread to most states in the northeast, Ohio, and Oregon. It is believed at present it is found in only about 20% of its potential range, and thus could spread much more widely if not brought under control.
Characteristics: This invasive is an annual and reproduces by seeds. Mile-a-minute weed is a self-fertile plant and does not need any pollinators to produce viable seeds. Its ability to flower and produce seeds over a long period of time (June through October) make mile-a-minute weed a prolific seeder. Seeds can survive in the soil for up to six years and can germinate at staggered intervals. Seeds are spread by many methods, including water and animals (birds, deer, squirrels and even ants). Vines are killed by frost and the seeds overwinter in the soil. Mile-a-minute seeds require an eight-week vernalization period at temperatures below 10 degrees Celsius (50 degrees Fahrenheit) to germinate the next season. Germination is generally in April through early June. Once the seeds germinate, the delicate vine grows rapidly, often smothering native vegetation. The vines and the undersides of leaves are covered with barbs that aid in its ability to climb. (see photo) Mile-a-minute has ocreae, or cup-shaped fused leaves, that surround the stems at nodes. Flower buds, and then flowers and fruit grow from these ocreae. (See photos) When the small, white, inconspicuous flowers are pollinated they form spikes of attractive blue, berry-like fruits, each containing a single glossy, black seed.
Why is this plant considered invasive? Because of its ability to grow rapidly, especially in disturbed areas, and smother native vegetation, mile-a-minute weed is considered a highly invasive species. In addition to natural areas, mile-a-minute can also invade nurseries, Christmas tree plantations, areas undergoing restoration, and disturbed areas such as power and pipelines.
Control: Physical removal of plants followed by monitoring for six years to look for seedlings produced by late-germinating seeds is a management technique. Also promising is the release of a tiny insect named the mile-a-minute weevil, Rhinocominus latipes. This small weevil is host-specific to mile-a-minute weed and has been successfully released and recovered in multiple locations in the U.S. In NJ, this weevil is being raised for release at the Philip Alampi Beneficial Insect Rearing Laboratory in Trenton, NJ. Mile-a-minute weevil feeding damage can stunt plants and can delay seed production. In the presence of competing vegetation, mile-a-minute weed can be killed by the weevil. Over time, mile-a-minute weevils have been shown to reduce spring seedling counts. Biological control of mile-a-minute weed is currently the most promising and cost-effective method, although physical removal and pre and post emergent herbicides may also be used. Given its prolific seed production it is unlikely that this invasive will ever be totally eradicated.