Invasion/Invasive

Abstract

My garden is being invaded by Japanese knotweed, as are those of my neighbors and those of many people who live in other places far from its native East Asia. I keep it more or less under control by eliminating individual extrusions, but I know that I am engaged in an open-ended struggle rather than a campaign leading to possible victory. The knotweed’s root system is extensive and deep, making it nearly impossible to extirpate once it has become established. In Massachusetts, the Japanese knotweed is one of sixty-six species that have been designated “invasive” by the Massachusetts Invasive Plant Advisory Group (a nonprofit organization that works in coordination with state and federal agencies). Like the other sixty-five species on the blacklist, it has been banned for importation, propagation, and sale within the state; but given the robustness and vigor of the plant, these official sanctions seem a bit like closing the barn door after the horse has run away. The same may be true of ostensibly more draconian measures promulgated in other polities: in the United Kingdom, the discovery of Japanese knotweed on a property may reduce its assessed value, and in parts of Australia it is formally prohibited.1