An Ode to Water Hyacinth, Vietnam's Invasive, Beautiful Aquatic Plant

Knotted gnarls of lush stems, leaves, vines; a verdant scrimmage of tangled plant matter kept afloat by buoyant bladders accented by pleats of pink petals that resemble the skirts of ballerinas trapped inside music boxes: the water hyacinth.

We currently live in a geological age known as the Anthropocene, so named because of humanity’s overwhelming influence on the planet. What is or is not natural is increasingly difficult to determine, let alone how one should assess the effects of the many rapid changes our species has caused. If the age were to have a symbol, none would be more fitting than the water hyacinth. Dubbed “the million-dollar weed,” “Bengal terror,“ “blue devil” and “enemy number one,” lục bình — as it is known in Vietnamese — savages ecosystems, stymies transportation efforts, clogs electricity grids and upends agricultural systems around the world. Yet, in Vietnam, the invasive plant has recently provided surprising benefits for economically disadvantaged communities, and may provide insights into how humans will interact with the natural world in the turbulent decades to come.

Lục bình growing in Long My District in the Mekong Delta. Photos by Paul Christiansen.

In Love and War

Water hyacinth played a curious role during the American War. Natural and expanded canals turned remote regions of the Mekong Delta into chessboards upon which opposing sides would place bases, sometimes within 1,000 meters of one another. Mines and barricades littered the lands in between. Guerrilla soldiers learned to sneak out at night and slip into the murky waters of intertwined waterways, slowly moving beneath a mat of water hyacinth, the only thing betraying their presence a small straw poking above the surface. They could thus move unnoticed right past enemy encampments.

The soldiers were not launching sneak attacks on their enemies, however. They were, after all, practically kids. Even during war, times of great danger, death and hardship, young love couldn’t be denied. They were using the hyacinth for cover so they could rendezvous with their sweethearts at other bases. No doubt the plant played silent witness to innumerable sweet nothings and moonlight kisses. 

Hearing this story while overlooking Long My’s weed-snarled canals wasn’t my first introduction to the complex history of water hyacinth, however. It has been reproducing out of control in my native America since it was inadvertently released during the 1884 Cotton States Exposition in New Orleans, and a brilliant piece of long-form journalism in the Atavist details an outlandish scheme to import and raise hippopotamus to keep it under control. Oddly, it failed not because the plan was unsound, but rather because of political gridlock and an inability to convince Americans that hippo meat was truly no stranger than cows or pigs when you think about it.

A Plant that Needs No Passport

In the 1990s, the world collectively spent nearly US$3 billion to try and control water hyacinth, and largely failed. You’ve no doubt seen it before. The dreadlocked leaves and thick stems float effortlessly on waterways throughout Vietnam and more than 50 nations on five continents. Classified as a free-floating hydrophyte, along with water cabbage and Salvinia, the Eichhornia crassipes, or water hyacinth, doesn’t anchor its roots in submerged soil like a water lily, instead, it drifts atop the surface the way clouds waft over empty fields.

Water hyacinth is native to South American jungles, but from the 16^th century through the 20^th century it was brought by biologists, botanists and travelers to Africa, Europe and Asia. It is believed to have arrived at the Bogor Botanical Garden in Java in 1894 for decorative use in ornamental baths and spread from there throughout the region for similar reasons. It slipped out from the Bangkok gardens and found its way into the Mekong River and expanded, a great green tendril, reaching down the slow-moving river. By 1902 it was brought to Hanoi, and from there spread into China and Hong Kong, where it was also used by locals to feed pigs. It’s surmised that in numerous places it made its way into local rivers, lakes, rice paddies and other natural bodies of water via accidental release. 

Water hyacinth has thrived thanks to a number of factors. In general, the hearty plant can survive in and adapt to a variety of conditions, including a range of water temperature and pH levels. While ideal conditions, including abundant nutrients, result in rapid growth, it can tolerate harsher climates and has been known to survive on damp soil for months and recover from leaves that have frozen during frosts. The world’s fastest-growing free-floating plant, under the right conditions, a mat of hyacinth can double in size in just a week or two.

Graphic by Hannah Hoang.

Moreover, like the way maggots thrive inside a decaying body, water hyacinth proliferates in polluted water. Factory sludge, household waste, chemical- and fertilizer-rich agricultural runoff change rivers and lakes’ natural nutritional compositions, allowing hyacinth to gorge itself, growing wildly out of control.

In its native habitat, the glorious, glorious, oh so glorious manatee feeds on hyacinth, which keeps them in check. However, in what is surely proof that god either doesn’t exist or is a vile, vengeful lord, manatees do not live all around the world. In areas where the plant has been introduced, no creature has made it a significant food source, and few insects or diseases impact it. 

Modern Vietnam’s Enemy Number One? 

"Though the two banks are just 40 meters apart, it takes me at least two to three hours to go to the other side by motor-boat [because of the plant]," said Tay Ninh resident Nguyen Huu Danh. Indeed, the unmitigated growth of hyacinth has made navigating waterways arduous at best. Needing to wait for currents to clear it, or having to hack a path stem by stem, directly translates to extra costs in shipping and supply chains, as well as numerous encumbrances for daily lives. Vo Thi Hoi, a small merchant from Dong Thap, explained that after 30 years, “we cannot carry goods from Dong Thap to Tay Ninh because the water hyacinth has blocked our way. I have suffered large losses due to late deliveries.”  

Photo via Moi Truong.

The thick green mats floating on the surface of rivers and lakes ensnare nets and lines, making fishing impossible as well. It forces fishermen to seek new waterways or find alternative income sources. Additionally, in some countries, water hyacinth has clogged hydroelectric power plants.

Not only does the weed entangle propellers, it harbors enemies, like the empty innards of a wooden gift horse. By flummoxing water flow, it provides ideal breeding grounds for mosquitoes carrying malaria, dengue and other diseases, while killing the many fish and amphibians that would normally eat the insects. The stagnant water also often acquires a foul odor and may be unusable for human use. 

Along with the immediate negative impacts on human lives, hyacinth upends ecosystems with unpredictable effects. In addition to out-competing native plants for light, nutrients and oxygen, it kills fish and other aquatic animals by changing the amount of sunlight that enters the water and throwing fragile biomes horrifically out of wack; spawning grounds decimated, migratory patterns upended and food chains shattered. The domino effect of this disruption is as wide-ranging as it is impossible to quantify.

In Vietnam, all of these problems come at great cost. In March 2019, Saigon authorities announced plans to spend more than VND28 billion (US$1.2 million) to clear municipal canals of water hyacinth, along with other weeds and trash. Constituting an estimated 30% of the total waste clogging the waterways, water hyacinth collection demands a significant portion of the VND1.1 trillion (US$47.4 million) the city spends to maintain its drainage system and the VND2.8 trillion (US$120 million) allocated to collecting garbage. 

Photo via Deep in the Delta.

Cleaning water hyacinth in the city largely involves laborious and low-tech methods, including stringing ropes across canals. Tidal currents result in a disgusting mashup of Styrofoam boxes, plastic bags, bottles, cans, tins and other urban detritus held together by thick hyacinth clumps which workers on boats must collect using long poles or, in some cases, generator-powered cranes bolted onto their skiffs.

In 2013, a group of scientists from the Industrial University of Ho Chi Minh City designed special water hyacinth-harvesting machines that they hoped would improve the clearing initiatives and reduce the physical toll of the workforce. They were first unveiled in Binh Thanh District, and the following year, department director Pham Danh said they were being rolled out in Binh Duong Province. The cutting machines were said to reduce costs to just VND220,000 (US$10) per ton of gathered hyacinth compared to VND700,000 (US$33) per ton when done manually. However, just one month after the cleaning operation in Binh Duong, the canal was again completely clogged in some places as the weed grew back.

Photo via Van Hien.

Authorities had said that if the machines proved successful, they would also be used in the Mekong Delta. No official report has been released assessing their efficacy, however, and considering that at the time of writing, a long rope stretches across the canal behind the Saigon Zoo gathering hyacinth that city workers regularly hand-clean, it's safe to assume the machines were not the great gear, grease and exhaust saviors the city had prayed for. 

There is nothing, however, stopping inventors and entrepreneurs from pitching in. The machines produced by numerous multinational companies are readily available for purchase, with prices ranging from US$2,000 for small models to well over US$100,000 for large industrial models. Theoretically, one could forgo brunch and instead spend a Saturday morning on a clogged canal killing plants to save the planet. 

Other nations similarly plagued by the water pest have experimented with a wide range of other ways to remove hyacinth. Various chemicals and pesticides can kill them, however they also put humans, other plants and animals at risk, and if not removed, the large amount of dead hyacinth that sinks to a river- or lake-bed also has significant effects. Releasing black fly larvae and other insects to feed on the plant has been proposed as a possible solution, though more research and experimenting needs to be performed before anything can be introduced on a large scale.

Is that a Silver Lining or a Piece of Tin Foil?

Photo via Life at Home.

This Dam Van Chu poem, which roughly translates to “I sit and knit the threads of night. / Hyacinth comforting the mind... / You walked the halfway / Let me bear the load of all the hardships... / Grind my teeth to tame the waves amidst the current. / My boat jostles, my hands clutched,” introduces the possible upside of the spread of water hyacinth in Vietnam.

In recent years, Vietnamese have begun using water hyacinth to craft a wide variety of products for domestic use and sale. Since 2011, the Phu Lam Export Weaving Cooperative in Dong Nai Province has used it, along with other local plants, to create baskets, trays, tables, chairs and crates that are then exported to Europe, Japan, South Korea and the US and sell for approximately US$20-30 each. Workers there can earn several million dong a month, which is a significant amount in the generally poor region and allows families to send their children to school.

Photo via Viet Craft.

Similarly, farmers in Hau Giang Province are able to supplement their income with an average of VND50,000 a day by weaving water hyacinth in their free time. Dried hyacinth can sell for VND16,000 per kilogram and prices are more stable than some other conventional crops. This has led people to plant and care for their plants, with hundreds of households now seeing it not as a weed, but as a potential source of income. 

Way back in 1996, IKEA became one of the first companies to begin using water hyacinth, largely sourced from the Mekong Delta, for home items such as napkin holders. The practice has even spread to northern Vietnam, with people in Ninh Binh using the plant to make handicrafts and as biofuel to grow mushrooms since 2005.  

Photo by Paul Christiansen.

Trinh Thi Long, program coordinator for water projects at WWF Vietnam, explains that his organization supports the use of the plant for such crafts because it can help remove it from infected areas. It is also preferable to using plants that are native and slow-growing. 

The economic viability of water hyacinth products, however, has had an unforeseen effect. Quality amongst the wild-growing plants varies widely, and thus people have begun planting and tending it. Those that don’t live on land with ponds or access to canals will even go to public lands to plant it. These cultivators ignore the wild hyacinth when doing so and thus don’t help address the issue, instead they simply add to the overall invasion.

Producing commercial bags, baskets, place mats and bins requires chemicals and lacquers which are not biodegradable. Thus, when discarded, they linger in landfills and ultimately contribute more negative materials to the planet than the plants would if otherwise allowed to decompose naturally.

In addition to home products, some entrepreneurs are feeding them to turtles and even using them to raise worms that are used for feeding fish, chickens, ducks, pigs and other livestock. Indian students have developed a way to make them into tampons as well as disposable plates, ready-to-plant biodegradable nursery pots, egg and fruit trays, cartoon models, toys, file boards, multi-purpose boards, and special canvas for paintings. It can also be utilized as ropes, cigar wrappers and, when combined with charcoal dust, made into briquettes. And while they are purported to give some people an allergic reaction even when cooked, some advocate for the eating of young shoots. 

In addition to using it for products, paradoxically people around the world are looking to hyacinth as a way to save water systems. When carefully managed, water hyacinth has proven an effective way to remove pollutants and actually improve water quality. If a strict control plan is in place, the hyacinth can be introduced and allowed to thrive and thus absorb a wide range of toxins, while also serving as a bioindicator for the presence of heavy metals. In Indonesia, China, and across Africa, people are using it for those purposes in a variety of waterways.

Photo via Dan Tri.

Critics warn of the accidental release or mismanagement of water hyacinth involved in these water-cleaning operations. Moreover, some studies conclude that the purposeful cultivation of water hyacinth for commercial purposes ultimately results in more harm than good. Doing so comes with all the problems of ecosystem disruption, the establishment of disease vectors, water degradation and disturbances to transportation and daily life. So while people harvesting the plant as it grows wild to use for a variety of commercial purposes may appear an ingenious solution, the inevitable transition to planting and tending it should cause distress. Yet wealth disparities and economic realities makes it difficult to fault those who look to it to escape poverty.

Our reckless and arrogant relationship with nature resulted in the spread of water hyacinth, and those same qualities seem to manifest themselves in our belief that we can harness it to rectify the pollution we have introduced into the world. Whether it's the Asian lady beetle in America or the cane toad in Australia, time and time again we’ve seen that adding more non-native species into an ecosystem cannot clean up the damage wrought from other invasive species. Yet, past experience always wilts in the face of profound hubris.

So what should we collectively make of water hyacinth? Certainly, it serves as a perfect symbol of our failure to co-exist responsibly with nature. But sitting along the Saigon River at sunset, I see a tuft float past alongside hulking barges weighed down with Mekong sand dredged for concrete that will soon constitute the foundation of some bubble tea shop or cellphone showroom; dinner boats ferrying overeating guests; and cargo ships crammed with fast fashion destined for distant shores. Sunlight slips through the skeleton of an in-progress skyscraper and falls on the floating plant with its single pink flower. I can’t smell it, but the subtle fragrance would no doubt satisfy the pleasure sensors of my simple animal brain.

Photo via Mississippi State University.

[Top photo via Jots and Jaunts.]