Mile-A-Minute weed is a scourge upon the landscape.It is entangled in my ornamental vines and overrunning the woods edge of my lawn.I don’t like it, and have been fighting it for a while. With diligence, we have convinced it to stop growing over the greenhouses. But I’m not willing to put down my guard just yet.
Many of our invasive weeds hitched a ride either as young seedlings or as dormant seeds remaining in shipping containers from other countries. Mile-a-Minute, also called Chinese Tear-thumb is no different. It came in on nursery containers of Rhododendrons from Asia in the late 1800s and has been spreading from Connecticut south to Virginia ever since. It is firmly ensconced in the Pennsylvania roadsides, disturbed areas and woods edges.
Mile-a Minute, scientific namePersicaria perfoliata,is an annual weed. Seeds first germinate in April, and seedlings appear shortly thereafter. It is a twining vine, and can spread over ground or climb up trees as far as 20 feet. Stems can grow six inches in one day. Hence the name. It is very prickly, with tiny sharp spines, almost barbs, along the stems and on the leaf veins. Thereby gaining the second common name of tear-thumb. It quickly covers native plants and shrubs smothering them and preventing photosynthesis.
Flowers are insignificant, but it forms clusters of round blue- purple metallic berries each containing one seed. The fruits are tasty to birds that generously spread the seeds as they fly, helping the plant in its plan of total world domination.
The leaves are edible, and have a slight lemon-citrus taste. Sometimes out of spite, I eat some as I walk past.
To combat the weed all that had been in our arsenal was herbicides and hand pulling. As it is spread so prolifically by seed- one plant can produce up to 2,000 seeds, alternative control methods were needed. Twenty years ago federal scientists started looking for a predator to eat the vines and leaves. Enter the Mile-a-Minute weevil,Rhinocominus latipes.Imported from Asia to combat the weed, it has been very successful in controlling the spread of Mile-A-Minute. In the last several years, highway departments in Maryland in conjunction with agriculture departments in New Jersey have been releasing the weevils as has the Pennsylvania Department of Conservation and Natural Resources. The bugs eat the leaves and also bore into the stems ultimately killing the plant and preventing seed production. Go weevils!
However, the plan is not to eradicate the weeds, just to keep the population in balance with the insects. I guess that is the yin and yang of wildlife management. If you have them in your yard, the fruits are now getting ripe. Remove them if you can to prevent the further spread of this pesky weed.