CALHOUN COUNTY, Mich. – An invasive mile-a-minute weed (Persicaria perfoliata) has been found at Albion College’s Whitehouse Nature Center in Calhoun County, officials said. What is mile-a-minute weed? Mile-a-minute weed is an annual vine that can grow up to 6 inches per day, or 25 feet in 6 to 8 weeks. Mile-a-minute weed infestations have been reported in 15 states across the United States. While mine-a-minute weed can be removed by hand, seeds can persist in the soil for up to six years.