Origin:
South America
Background: Fanwort, known commonly by its scientific name Cabomba caroliniana, is one of six aquatic plant species recognized by
New York
State
as a non-native aquatic invasive species. Native to
South America
, Cabomba has been introduced all over the world, mainly due to the aquarium plant trade. Its delicate, fan-like fronds make it popular for aquaria. This plant is listed as a banned invasive in
Connecticut
, and as a noxious weed in several other
U.S.
states.
While the most common method of introduction is the dumping of old aquarium plants, Cabomba is also capable of rapidly spreading on its own by stem fragments or rhizomes. In fact, a 100-meter strip of Cabomba plants was hand-pulled by divers in
Lake Macdonald
,
Queensland
,
Australia
. Within two weeks divers had difficulty finding evidence of the cleared area!
Habitat: Cabomba is a rooted plant that grows in the mud of slow flowing or stagnant freshwater. It may grow in streams, small rivers, ponds, lakes, reservoirs, ditches, and canals. This species requires permanent contact with water, although it can survive wide fluctuations in water depths. Cabomba grows best on silty substrates in nutrient-rich waters with low pH. Cabomba’s ability to grow in turbid, or cloudy, water is unusual and somewhat unsettling, as turbid water usually limits the growth of aquatic weeds.
Ecological Threat: Cabomba is an extremely competitive and persistent plant capable of forming dense mats that crowd out native plants. Because most of its growth occurs underwater, it can be overlooked. Once established, the plant can clog waterways, disrupting natural flow as well as recreational activities, particularly fishing and boating. In cases of severe infestation, Cabomba can raise water levels to the point of overflow. Despite its tendency to reduce biodiversity, Cabomba is now considered beneficial habitat for fish and other aquatic species in several areas of the Peconics.
Cabomba has already overtaken
Lower
Yaphank
Lake
in Brookhaven town, hindering recreational use of the water by residents. If the weed goes unchecked, it could infest the area’s entire watershed. Cabomba is also present in the
Peconic
River
, and is well-established in other areas throughout the Peconics. The weed has been present here for decades, probably originating from a few aquarium plants.
Description and Biology:
Plant: Fully submerged, perennial freshwater aquatic. Occasionally leaves and flowers grow above the water’s surface. Branched stems grow up to 10m (33 ft) long, scattered with white or reddish-brown hairs.
Leaves: Underwater leaves are divided into fine branches approximately 5 cm (2 in) across, giving the plant its characteristic feathery, fan-like appearance. Floating leaves are small, diamond-shaped, and occur on the flowering branches.
Flower, fruit, and seeds: White or pale yellow solitary flowers (< 2 cm across) emerge on stalks from the tips of the stems.
Reproduction: Spreads via rhizomes or from vegetative reproduction by stem fragments (i.e., a detached piece of the plant can regenerate into a full plant as long as it has at least one pair of leaves).
Identification: Cabomba may be easily confused with other aquatic species. The fact that it is a submerged plant often makes identification more difficult. Two groups of aquatic plants that may be confused with Cabomba are the hornworts (Certaophyllum spp.) and the watermilfoils (Myriophyllum spp.). As shown in the pictures below, these plants look similar to Cabomba; decisive identification may require an expert.
Prevention: The most important step in stopping the further introduction of Cabomba caroliniana to the Peconic Estuary System is prevention. As a popular aquarium species, Cabomba finds its way into the natural environment when aquarium owners dump the contents of their aquarium into a lake, river, or stream. Please do not dump unwanted aquatic plants!
In
Suffolk
County
it is illegal to introduce any material containing an invasive non-native aquatic animal or plant into any river, stream, lake, pond, wetland, or storm drain (SC Res# 1108-2005). Violators of this law are subject to a fine of up to $1,000.
In addition, boaters can spread Cabomba by transporting it from one waterway to another if it is attached to the hull, anchor line, engine, or other part of the boat. Boaters should clean their boats thoroughly before moving between waterbodies. See our invasive species stewardship page for more information on preventing the spread of Cabomba.
Control:
