Eichhornia crassipes
• Introduced from South America in the 1880’s as an ornamental plant.
• Now invades Asia, Africa, as well as North and South America.
North American Distribution
MorphologyMorphology• Leaves broadly ovate
and circular, 4-8 inches in diameter with numerous longitudinal veins.
• Leaves grow in whorls.• Leaf stalks are bulbous
and spongy.• Flowers grow on stalk
20 inches tall with spike of numerous, showy flowers (8-15).
MorphologyMorphology• Flowers have 6
purple to blue to lavender petals with the upper ones having a yellow, blue bordered central spots.
TaxonomyTaxonomyDivision: Magnoliophyta
Class: LilopsidaSubclass: CommelinidaeOrder: Pontederiales
Family: Pontederiaceae Genus: Eichhornia crassipes
Not a member of the True Hyacinth familyMore closely related to native pickerelweed
ReproductionReproduction
• Sexual reproduction produces numerous seeds.– Each inflorescence can produce 3,000
seeds that can remain viable for 15-20 years.
• Most reproduction is vegetative. – Reproduces rapidly from rhizomes,
offsets, and tubers to form dense mat, sometimes dense enough to walk on.
Ecological ImpactEcological Impact
• Dense mats reduce light penetration to other aquatic biota.
• Reduce the amount of dissolved oxygen in the water.– Changes invertebrate community, which affects
fish.
• Decaying plants causes spike in nutrients, also causing spike in algal blooms also leading to reduced dissolved oxygen and light penetration.
Economic ImpactsEconomic Impacts
• Chokes off flow of water.– Access to shore restricted.– Transportation through water way also restricted.– Reduced flow means less available water for
irrigation.– Clogs irrigation pumps.
• Impacts mosquito control by hindering insecticide application and provides habitat for breeding insects.– Reduced water circulation.
ControlControl
• Mechanical– May be picked from water.– Specialized machines are used to harvest
from colonized waters.
• Biological Control– There are many natural predators of
waterhyacinth.
ControlControl
• Biological Control (cont.)– Four insects are commonly used:
• Neochetina eichhorniae (weevil)• N. bruchi (weevil)• Niphograpta albiguttalis (moth)• Orthgalumn terebrantis (mite)
• Healthy plant community must be established in order to establish control communities.
ControlControl
• Suppression may take many years.– Methods are being tested to use
combination of mechanical, biological and herbicidal (diquat) methods to make control more expedient.
• Control can be very successful.
Works Cited
• Driesche, R. V., Blossey, B., & Hoddle, M. (2002). Water Hyacinth. In . Mark (Ed.), Biological
Control of Invasive Plants in the Eastern United States (pp. 41-64). : USDA Forest Service.
• Osei-Agyemang, M. (2003). Introduced Species Summary Project Water Hyacinth
(Eichhorinia crassipies). Retrieved Sep. 13, 2008, from http://www.columbia.edu/itc/cerc/danoff-burg/invasion_bio/inv_spp_summ/water%252520hyacinth.html