Description:
Fanwort is a submersed, floating (often rooted), perennial, with short, fragile rhizomes. The erect shoots are upturned extensions of the horizontal rhizomes. The shoots are grass green to olivegreen or sometimes reddish brown. The leaves are of two types: submersed and floating. The fan-shaped submersed leaves are finely divided and arranged in opposite pairs on the stem. The floating leaves (when present) are small and inconspicuous, with an alternate arrangement. The floating leaves are less than 1/2 inch long and less than 1/4 inch wide and the leaf blade attaches to the center, where there is a slight constriction. The flowers are white and small (less than 1/2 inch in diameter), and they float on the water surface (Gibbons 1993; Radford 1968; Orgaard 1991).

• Mechanical: In the South, drawdowns have been used to reduce fanwort growth. Extreme drying is required to prevent regrowth from seed (Gibbons et al. 1993).
• Biological: Grass carp will eat fanwort, but it is not a preferred food (Gibbons et al. 1993). No research is currently underway on other biocontrol agents.
• Herbicide: According to Westerdahl and Getsinger (1988), endothall provides excellent control, but it is a contact herbicide only. Fluridone also provides good control. However, some reports indicate that fanwort is less sensitive to herbicides available in Washington than other aquatic Refer to the State Noxious Weed Control Board site

For More Information:
Detailed information about Fanwort is available at the Washington State Noxious Weed Control Board Web Site.