The stem attaches to the floating leaf blade at the center where there is a slight constriction. Fanwort is a rooted aquatic plant with a limited distribution in the Northwest. In Washington it is restricted to side-channels of the Columbia River near Longview. In contrast to other rooted aquatic plants, fanwort is reported to obtain nutrients important for growth from the water column rather than the sediment. Fanwort has been in Cullaby Lake, on the north coast of Oregon, for at least 10 years where it creates severe nuisance conditions.
Fanwort is a serious aquatic weed as far north as upstate New York and Michigan.
It clearly has the ability to grow and create serious weed problems in Washington. Like many problem aquatic plants, fanwort can regenerate from small stem fragments. Fanwort stems become brittle in late summer, which causes the plant to break apart, facilitating distribution and invasion of new water bodies. Fanwort is self-pollinating in the South and seeds readily germinate. Yet, seeds collected in New Jersey failed to germinate.