Smartweed, Knotweed (Polygonum species)
Smartweeds are valuable wetland plants. Their seeds provide an abundant source of food for aquatic wildlife. More than 20 species occur in Michigan, including several that are non native. Nodding smartweed (Polygonum lapathifolium) is one of the more common species, and quite variable, producing flowering individuals of only a few inches in height and sometimes colonizing marsh flats in extensive patches consisting of six foot tall plants.