Waterhyacinth

By Jason Zarnowski

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