What could be prettier than a field of blue flowers, nodding in a warm breeze, their petals like chips of the sky? If you are passing by a field of lavender in the South of France, then, yes, it's a glorious sight. But if you are driving somewhere in Florida and the showy blue flowers belong to the water hyacinth, the "field" may actually be a smothered pond, lake, canal, or river, and what you are seeing is a monster worthy of The X-Files.

Water hyacinth, scientifically known as Eichhornia crassipes, has been called not just the worst weed on Earth, but the worst vascular plant on Earth. It can double its biomass in a week, and does so all over the tropical and subtropical world. This South American native literally obliterates bodies of water with a solid mat of vegetation above and tons of decaying matter beneath, killing fish, destroying native plants and wildlife habitat, making navigation, fishing and recreational use impossible, and allowing the proliferation of disease-causing mosquitoes. Nineteen U.S. states report battles with the invader. In Africa, every freshwater lake and river—even the mighty Lake Victoria—is infested with rafts of water hyacinth. Sounds like this case is too big for even Mulder and Scully!

Its only limitations are cold winters, so it is still grown in northern climes, as its beautiful lavender-blue flowers with the yellow "eye" are fancied by owners of fish ponds. When strictly controlled, the plants actually do clarify the pond water and provide shade and places for the fish to spawn. Perhaps that's why people have smuggled them to Hawaii; certainly there's no other way for this pest to have crossed the Pacific. Those flowers sure are pretty!

Beauty becomes the Beast
The first reported appearance of water hyacinth in the U.S. was at the 1884 Cotton States Exposition in New Orleans. When the Expo ended, people were delighted to receive samples to "beautify" their ponds and rivers back home. Photographs of the St. John's River in Florida just a couple of years later show how the surface of this wide river was carpeted completely by the plants. It was reported that not even a paddle-wheel steamboat could plow through, so thick was the mat of water hyacinth.

Eventually, Congress took notice, and in 1899 passed the Rivers and Harbors Act, which authorized the U.S. Army Corps of Engineers (USACE) to attack water hyacinth in the St. John's by crushing or removal; this was amended in 1902 to add chemical methods. Sodium arsenite, a toxic chemical, was used until 1905. In 1899, the Florida Legislature passed a law against planting it anywhere in the state. (How many homeowners and nurseries have unwittingly broken this little-known regulation?)

The War Machines
So, for over 100 years, Florida has been at war with this beautiful enemy. A whole industry sprang up of "war machines:" giant bulldozers, draglines and trackhoes, massive conveyor belts, harvesters first propelled by paddle-wheels and later by more modern engines, barges large enough to carry cranes, small barges with metal scoops and rakes, shredders, crusher boats (also known as Kennys), elevator boats, saw boats, destroyer boats, hi-bailers... every machine just shy of Sherman tanks and nuclear submarines has been deployed in this losing battle. By the early 1960's, over 125,000 acres of fresh water bodies were being smothered.

It's not hard to imagine the terrible side effects of using these mechanical control machines: native plants and all manner of wildlife are accidentally killed. These machines, no matter how powerful or sophisticated, have been proven over the decades to be ineffective. They can chomp through only about two acres a day-not as fast as the plant can reproduce itself. To make matters worse, the smallest remains of the macerated water hyacinth may still be able to vegetatively reproduce.

The Bull Hyacinth
The central flower spike of Eichhornia crassipes may shoot up to three feet. When they get that robust, they are grudgingly complimented with the name, "bull hyacinth." Each plant continually sends out runners, or stolons, of plantlets, which weave together into a tapestry which weighs tons. It also reproduces by seeds, which can lay dormant during droughts, only to germinate when conditions are right. The leaves and stems are perfectly designed to be as buoyant as a personal flotation device. Great masses of hairy black roots hang down underneath; they don't need to be rooted to the lake bottom to provide nutrients. Wind and currents carry water hyacinths from place to place. When first scooped out, an acre of water hyacinth weighs 200 tons. An acre of water hyacinth will deposit 500 tons of decaying material beneath it every year. It's the decaying of that material which uses up the dissolved oxygen (DO) in the water. Without sufficient DO, fish die.

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