giant salvinia

Hydropteridales > Salviniaceae > Salvinia molesta D. S. Mitchell
Synonym(s): kariba weed, salvinia, water fern

Giant salvinia is an aquatic fern with floating leaves that are 0.5 to 1.5 in. (2.5-3.8 cm) long, oblong, and vary in color from green to gold to brown. The surfaces of the leaves have rows of arching hairs that look like little egg-beaters. When young, leaves are smaller and lie flat on the surface of the water. After maturing, giant salvinia forms chains of leaves that run together to form thick mats on the surface of the water. These mats restrict oxygen and light availability causing death of the primary producers and disrupting the aquatic food chain. Submerged fronds are "stringy" and resemble roots. Plants reproduce by spores and by budding of broken stems or attached nodes. Giant salvinia is on the Federal Noxious Weed list and can invade most any type of aquatic system. The plant is native to South America and was first introduced into North America as an ornamental.


Identification, Biology, Control and Management Resources


Selected Images from Invasive.org

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Plant(s); closeup with quarter for size reference
Scott Robinson, Georgia Department of Natural Resources, Bugwood.org
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Plant(s); Close up of giant salvinia plants
Scott Robinson, Georgia Department of Natural Resources, Bugwood.org
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Foliage; habit
Forest & Kim Starr, U.S. Geological Survey, Bugwood.org
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Feature(s); the hairs form an 'egg-beater' shape at the tips
Mic Julien, Commonwealth Scientific and Industrial Research Organization, Bugwood.org
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Feature(s); Sporangia
Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
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Plant(s);
Troy Evans, , Bugwood.org
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Plant(s);
Troy Evans, , Bugwood.org
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Plant(s); Giant salvinia is a fast-growing fern that can clog ponds and lakes. Forming mats up to 2 feet thick, the plant gobbles up oxygen and blocks sunlight needed by other water dwellers.
Scott Bauer, USDA Agricultural Research Service, Bugwood.org
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Infestation; This canal was completely covered by giant salvinia in a few short months. A dinner plate size patch of the plant was first noticed in the canal in late July. This picture was taken in early December 1999.
Scott Robinson, Georgia Department of Natural Resources, Bugwood.org
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Infestation; A large infestation in Mississippi. Photo taken Sept 22, 2004. See photo# 1333010 for picture of infestation 41 days earlier.
Kenneth Calcote, Mississippi Department of Agriculture and Commerce, Bugwood.org
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Damage; covering a farm pond restricts commercial and recreational use and degrades aesthetics
Ted D. Center, USDA Agricultural Research Service, Bugwood.org
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Control; A Georgia DNR fisheries technician treats the infestation of giant salvinia. DNR is attempting to eradicate the plant in this location.
Scott Robinson, Georgia Department of Natural Resources, Bugwood.org
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Feature(s);
Victor Ramey, University of Florida, Bugwood.org
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Invasive Reference(s):

Check Invasive.org for most current lists.
  • Federal Noxious Weed List
  • Alabama - IPC List
  • Arizona - Noxious Weed Law
  • California - Noxious Weed Law
  • California - Invasive Plant Inventory
  • Colorado - Noxious Weed Law
  • Connecticut - Noxious Weed Law
  • Georgia - EPPC list
  • Massachusetts - Noxious Weed Law
  • Mississippi - Noxious Weed Law
  • Nevada - Noxious Weed Law
  • North Carolina - Noxious Weed Law
  • Oregon - Noxious Weed Law
  • South Carolina - Noxious Weed Law
  • Tennessee - Noxious Weed Law
  • Texas - Invasive Plant List
  • Vermont - Noxious Weed Law
  • Invasive Plants: Western North America
  • Invasive Plant Atlas of New England
  • Invasive Plant Atlas of the Mid-South


External Links


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USDA Forest Service Bugwood University of Georgia