Carolina fanwort

Scientific Name: Cabomba caroliniana

Troy Evans, Bugwood.orgCopyright Info

Graves Lovell, Alabama Department of Conservation and Natural Resources, Bugwood.orgCopyright Info

Identification: Carolina fanwort is a plant that grows rooted in the mud of stagnant to slow-flowing water. This plant is fully submerged except for occasional flowers and floating leaves on the surface. However, parts of this plant can survive free-floating for six to eight weeks. Stems are branched and covered with white or reddish-brown hairs.

The plant’s submerged parts are slimy due to the leaves’ secretions. The underwater leaves are about 2 inches (5 cm) across and are divided into fine branches, resulting in a feathery, fan-like appearance. Flowering branches grow above the surface and have small leaves that are diamond-shaped. The single flowers are less than 1 inch (2 cm) across and range in color from white to pale yellow and may also have a pink or purplish tinge. The plant is also known as Carolina water-shield, fanwort, fish grass, green cabomba, Washington grass, and Washington-plant.

Size: Mature plant size varies with water depth. Stems are usually less than 10 feet (3 meters) long, but they can grow up to 33 feet (10 meters) in length.

Native Range: Carolina fanwort is native to southern Brazil, Paraguay, Uruguay, Argentina, and the southern and eastern United States.

Table 1. Great Lakes region nonindigenous occurrences, the earliest and latest observations in each state/province, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Cabomba caroliniana are found here.

Full list of USGS occurrences

State/ProvinceYear of earliest observationYear of last observationTotal HUCs with observations†HUCs with observations†
Michigan193520169Clinton; Huron; Kalamazoo; Lower Grand; Muskegon; Pere Marquette-White; St. Joseph; Thornapple; Upper Grand
New York199920143Northeastern Lake Ontario; Oneida; Salmon-Sandy
Ohio200820082Cuyahoga; Southern Lake Erie

Table last updated 9/30/2019

† Populations may not be currently present.

* HUCs are not listed for areas where the observation(s) cannot be approximated to a HUC (e.g. state centroids or Canadian provinces).

Means of Introduction: The aquarium and water garden trades have spread Carolina fanwort throughout the world. Large numbers of this plant are sent from Florida to the rest of the United States for commercial use. Fanwort is also grown commercially in Asia for export to Europe and other parts of the world. Small-scale, local cultivation occurs in some areas, and some introductions probably occur due to aquarium releases or escapes.

Fanwort stems become brittle in late summer, which causes the plant to break apart. Small pieces of fanwort can hitch a ride on boats, trailers, and equipment, allowing it to be transported to new bodies of water where the plant can then become established.

Status: Carolina fanwort is widely established in many North American states. The first Great Lakes sighting was in the Lake Michigan drainage in 1935. It has since been reported in New York, Pennsylvania, Ohio, Michigan, Illinois, Indiana, and Ontario.

Remarks: Carolina fanwort is sensitive to drying-out and requires permanent shallow water.

Author: Illinois-Indiana Sea Grant

Contributing Agencies:
NOAA Sea Grant GLRI Logo

Revision Date: 4/24/2012

Citation for this information:
Illinois-Indiana Sea Grant, 2019, Carolina fanwort: U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, and NOAA Great Lakes Aquatic Nonindigenous Species Information System, Ann Arbor, MI,, Revision Date: 4/24/2012, Access Date: 10/13/2019

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.