Human Flower Project

Monday, January 31, 2005

Water Hyacinth—Africa’s Not-So-Pretty Settler

A native of Brazil, the water hyacinth has become the worst aquatic weed in the world. The U.N.‘s Food and Agriculture Organization (FAO) has been fighting back against this greedy beauty across Africa for a decade, with help from a weevil.

Eichhornia crassipes

Photo: Ricardo Labrada

Too much of a good thing—way too much.

The water hyacinth (Eichhornia crassipes (Martius) Solms-Laubach) has made a pest of itself across much of the globe, especially in tropical Africa, where it’s grown into a flowering strangler. According to an FAO report by Ricardo Labrada of the Plant Protection Service, the water hyacinth advanced quickly due to its flowery good looks. “Its spread started with its deliberate introduction into North America from Brazil, in the late 19th century, as an ornamental in ponds and subsequently escaped cultivation.” Water hyacinth seems to have arrived in Africa in the 1980s.

Water hyacinth clog

Lake Victoria, Uganda

Photo: Ricardo Labrada

Here’s an example of how this lovely plant has become an invader. During the 1990s “dense mats” of water hyacinth had clogged big stretches of Lake Victoria in Uganda, choking off fishing and even transportation. The water hyacinth is not just a water dweller but a vaporizer, its lush leaves “sweating” so much moisture into the air that it “alters the water balance of entire regions.”

Water-hyacinth infestations can also slow the output of electrical power stations, imperil local agriculture, become breeding grounds for poisonous snakes, and bring disease.

The FAO’s weed controls in Africa have included many kinds of measures: surveillance, training, greater inter-country cooperation, and principally the introduction of a natural enemy—Cyrtobagous salviniae, a species of weevil. The FAO says that breeding and releasing this hyacinth-predator is preferable to fighting back with chemicals.

There’s a lot of fascinating information on the FAO site, including a slide show of the ongoing struggles again water hyacinth, water fern and other World Wide Weeds.

Thinking about sneaking a flowering plant back home from your trip to the tropics? Look what the water hyacinth has done, and reconsider.

(Note: Welcome to our recent visitors from Togo. Please let us hear from you about flowers, wanted and unwanted.)