Invasive Plant Factsheet
Although considered a noxious weed, this plant of Eurasian origin is still available for sale. It was introduced as a contaminant in ships’ ballast and as a medicinal herb and has spread along roads, canals, and drainage ditches to degrade wetlands since the early 1800s. Nearly all states and many Canadian provinces have been infested, and it is listed as invasive in Arlington and Alexandria.
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