Description:  Fanwort is a rooted, submersed, perennial aquatic plant which grows from short, fragile underground stems with fibrous roots. Its underwater leaves are either green or reddish-purple, are opposite on the stem, and are finely divided into segments in a fan-shaped arrangement. Floating leaves may be present during flowering and are small, inconspicuous and oblong in shape. Flowers are solitary, white to pinkish in color, and are produced on stalks below the water surface. Fanwort's flowers will float on the water surface for a brief time, allowing cross-pollination to occur. Fanwort spreads .lost frequently by stem fragments or underground roots; however, new plants can also be produced from seed.

Habitat:  Fanwort grows in freshwater lakes and ponds, and slow-moving streams and ditches in water from three to ten feet deep. In some locations, it has been found at much greater depths. Alkaline waters can inhibit its growth; it is typically found inhabiting waters with a pH between 4.0 and 6.0.

 

Threats: Fanwort is an extremely persistent and competitive plant. Under suitable conditions, fanwort can form dense stands, crowding out native aquatic plants. Once established, it can clog water flow and interfere with recreational and agricultural water use.

Distribution:  Fanwort is a native of the subtropic-temperate regions of eastern North and South America. It is common in the southeastern United States along the coastal plain from Virginia to Florida. It is also known to occur in southern New Hampshire, Massachusetts, New York, Pennsylvania, southern Michigan, southern Illinois, Kansas, Missouri, eastern Oklahoma, eastern Texas, Washington, and northern Oregon.

---

---

(This fact sheet is one in a series on invasive exotic plants in Vermont and it 's cooperative project between the Departments of Environtental Conservation and Fish & Wildlife, of the Vermont Agency of Natural Resources, and The Nature Conservancy of Vermont. Spring 1998.