Polygonum Amphibium, or more commonly know as Water Knotweed, is a forb/herb (a forb/herb is a non-woody plant that is not a grass) with green foliage and yellow flowers of the genus Polygonum. It has a moderate growth rate and a height of 0.1 feet at maturity. Its duration is perennial which means it will grow year after year. It's active growth period is summer, blooms during late spring and is intolerant of shade. Polygonum Amphibium or Water Knotweed's floral region is North America US Lower 48 and Alaska, specifically in the states of Alaska, Arkansas, Arizona, California, Colorado, Connecticut, Delaware, Iowa, Idaho, Illinois, Indiana, Kentucky, Louisiana, Massachusetts, Maryland, Maine, Michigan, Minnesota, Missouri, Mississippi, Montana, North Carolina, North Dakota, Nebraska, New Hampshire, New Jersey, New Mexico, Nevada, New York, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Utah, Virginia, Vermont, Washington, Wisconsin and Wyoming.
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