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

Morphology 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).

Morphology Flowers have 6 purple to blue to lavender petals with the upper ones having a yellow, blue bordered central spots.

Taxonomy Division: Magnoliophyta Class: Lilopsida Subclass: Commelinidae Order: Pontederiales Family: Pontederiaceae Genus: Eichhornia crassipes Not a member of the True Hyacinth family More closely related to native pickerelweed

Reproduction Sexual reproduction produces numerous seeds. –Each inflorescence can produce 3,000 seeds that can remain viable for years. Most reproduction is vegetative. –Reproduces rapidly from rhizomes, offsets, and tubers to form dense mat, sometimes dense enough to walk on.

Ecological 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 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.

Control Mechanical –May be picked from water. –Specialized machines are used to harvest from colonized waters. Biological Control –There are many natural predators of waterhyacinth.

Control 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.

Control 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 ). : USDA Forest Service. Osei-Agyemang, M. (2003). Introduced Species Summary Project Water Hyacinth (Eichhorinia crassipies). Retrieved Sep. 13, 2008, from burg/invasion_bio/inv_spp_summ/water% hyacinth.html