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 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 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. 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%2525 20hyacinth.html