Pacific Island Ecosystems at Risk (PIER)

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Neptunia plena
(L.) Benth., Fabaceae
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Present on Pacific Islands?  no

Primarily a threat at high elevations?  no

Risk assessment results:  Risk assessment from the Government of Queensland, Australia (PDF format)

Other Latin names:  Mimosa plena L.

Common name(s): [more details]

Chinese: jia han xiu cao

English: water dead and awake, water sensitive

Habit:  aquatic herb

Description:  "Water mimosa is an aquatic floating perennial herb that attaches to the bank at the waters edge and sends down a taproot. Stems grow out over the water and form a spongy, fibrous covering between the nodes. Fibrous (adventitious) roots grow from the nodes. The rooted land form has smaller leaves and flowers, and has no spongy floating tissue. Leaves are olive green and are arranged in opposite pairs along the stem. When disturbed or touched the leaflets close up. Water mimosa flowers are yellow, ball-shaped and grow from the base of the leaves" (Fact sheet on Neptunia oleracea and Neptunia plena from the Queensland Government).

Habitat/ecology:  "Water mimosa takes root on the banks of watercourses and grows out over the water surface, forming floating rafts. Within its native range, water mimosa is a common floating plant in freshwater pools, swamps and canals at low altitudes of up to 300 m. When water levels fall during the dry season, the plants often perish. The plants prefer slow-moving water 30-80 cm deep, full sun and hot, humid conditions. Shade, brackish water and saline soil adversely affect plant growth. Under favourable conditions, water mimosa grows out from the banks to form floating rafts of dense interwoven stems. These can be dislodged by water movement (especially during floods) and are soon replaced by more water mimosa. These floating rafts can: restrict water flow in creeks, channels and drains, impede recreational water sports and boating access, increase water loss through evapotranspiration, reduce water quality by preventing light penetration  and reducing oxygenation of water, create a favourable habitat for mosquitoes, reduce fish activity, cause the death of native, submerged water plants and fish and replace native wetland plants" (Fact sheet on Neptunia oleracea and Neptunia plena from the Queensland Government).

Propagation:  Seed and plant pieces carried by water (Fact sheet on Neptunia oleracea and Neptunia plena from the Queensland Government).

Native range:  Southern United States (Texas), Mexico, Central and South America (GRIN).

Presence:

Pacific Rim
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
Australia
Australia (continental)
Queensland introduced
invasive
Queensland [Australia] Government (2009)
China
China
China (People's Republic of) introduced
ILDIS Co-ordinating Centre (2013)
Colombia
Colombia
Colombia (Republic of) native
ILDIS Co-ordinating Centre (2013)
Costa Rica
Costa Rica
Costa Rica (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Ecuador (Mainland)
Ecuador
Ecuador (Republic of) (continental) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
El Salvador
El Salvador
El Salvador (Republic of) native
ILDIS Co-ordinating Centre (2013)
Guatemala
Guatemala
Guatemala (Republic of) native
ILDIS Co-ordinating Centre (2013)
Honduras
Honduras
Honduras (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Indonesia
Indonesia
Indonesia (Republic of) introduced
Space, James C./Waterhouse, Barbara M./Newfield, Melanie/Bull, Cate (2004)
Malaysia
Malaysia
Malaysia (country of) introduced
Space, James C./Waterhouse, Barbara M./Newfield, Melanie/Bull, Cate (2004)
Mexico
Mexico
Mexico (United Mexican States) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Nicaragua
Nicaragua
Nicaragua (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Panama
Panama
Panama (Republic of) native
ILDIS Co-ordinating Centre (2013)
Perú
Perú
Perú (Republic of) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Singapore
Singapore
Singapore (Republic of) introduced
Space, James C./Waterhouse, Barbara M./Newfield, Melanie/Bull, Cate (2004)
Singapore
Singapore
Singapore (Republic of) introduced
invasive
Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. (2009) (p. 63)
Naturalised
Also reported from
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
United States (continental except west coast)
United States (other states)
United States (other states) native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Texas

Control: 

Physical:  "There are no chemicals registered specifically for use against water mimosa. In most instances, the most appropriate method of control is to physically remove the infestation. This can be done by removing all plant matter from the infested water body and pulling plants out of the surrounding banks, ensuring removal of the attached root system. This should be repeated on a regular basis until regrowth ceases. All removed plant parts should then be disposed of in an appropriate waste facility or rubbish bin" (Fact sheet on Neptunia oleracea and Neptunia plena from the Queensland Government).


Need more info? Have questions? Comments? Information to contribute? Contact PIER! (pier@hear.org)

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This page was created on 31 AUG 2009 and was last updated on 16 MAY 2017.