Water hyacinth (Eichhornia crassipes) is a beautiful aquatic plant that is popular for ponds and water gardens. However, it can also become invasive and take over waterways if not properly managed. Here is a guide on how to successfully plant water hyacinth while keeping it under control.
Choosing the Right Location
When planting water hyacinth, it’s important to choose a location that gets full sun and has still or slow-moving water. Stagnant water allows the plants to spread more rapidly. However, be cautious about planting water hyacinth in public ponds or waterways, as it is banned in some states due to its invasive potential. Container ponds or backyard ponds are better options for managing the spread.
Obtaining the Plants
Water hyacinth can be purchased at many aquarium and water gardening stores. Choose plants with healthy foliage and no signs of disease. It’s best to start with just a few starter plants, rather than dumping bunches of water hyacinth into a pond all at once. This gives you a chance to assess their growth rate and how quickly they spread in your specific environment.
Introducing the Plants to the Pond
When adding water hyacinths to a pond, simply place the starter plants in the desired location and let them float freely. Their bulbous stems will keep the plants afloat. If needed, use a nylon string to anchor the plants in place, attaching the string to a brick or stone on the bottom of the pond. But floating freely is the preferred method. The plants will quickly acclimate and begin multiplying.
Caring for Water Hyacinth
Once established, water hyacinth requires very little care. They flourish in warm temperatures and full sun. The most important maintenance task is keeping their growth in check. As the name suggests, these plants really do “hyacinth” across the water’s surface! Prune the plants when they cover more than 60% of the surface area. Simply remove excess plants and toss them in the compost bin or trash. With frequent thinning, water hyacinth can make a beautiful and controlled addition to any water feature.
Overwintering Water Hyacinth
In zones 8-11, water hyacinth can be grown as a perennial aquatic plant. The plants will die back in winter and return in spring. In colder climates, water hyacinth is treated as an annual. They can be overwintered indoors in an aquatic plant container under bright light. However, most gardeners find it easier to replace water hyacinth with new plants each spring.
A Note on Invasiveness
Water hyacinth is notoriously invasive in warm regions if allowed to escape into lakes, rivers, and ponds Please be a responsible gardener by properly disposing of excess plants Never dump them into public waterways. With some basic diligence, you can enjoy water hyacinth as a decorative aquatic plant while keeping it from becoming a nuisance or threat to native species.
What is Water Hyacinth?
Water hyacinth (Eichhornia crassipes) is a large aquatic plant native to the Amazon basin. Its thick, waxy, oval-shaped leaves are 4-8 inches across and branch out from the center of the plant on modified stems that may rise as much as 1 meter above the water surface. The mass of fine roots that hang in the water underneath the plant are dark purple or black with small, white root-hairs. The stems are spongy, bulbous stalks (called petioles) that contain air-filled tissues that keep the plant afloat. When flowering, the stalks support 8 – 15 blue-violet flowers with six petals each, with one petal being deeper violet with a yellow spot.
Water hyacinth produces thousands of seeds each year, which can remain viable for up to 30 years.
One of the fastest growing plants known; water hyacinths can double populations in two weeks. Some populations in Southeast Asia have been documented to grow up to 5 meters per day. The plant is capable of reproduction by two vegetative methods: seeds and horizontal stems. Flowers open briefly during the summer before beginning to wither. When all the flowers have withered, the stalk gradually bends into the water and seeds are released and sink to the soil where they can remain viable for up to 30 years. Water hyacinth can also produce vegetatively by producing short runner stems (stolons) from the base of the plant to form daughter plants. Fragmentation, or breaking into smaller pieces, may occur by wind or wave action or the propellers of motor boats. Once broken apart, plant fragments are easily transported to new areas where they can reproduce and cause another infestation.
Water hyacinth mats are capable of attaining incredibly high plant density and biomass. A single hectare can contain more than 360 metric tons of plant biomass.
Water hyacinth is considered a noxious weed species in more than 50 countries. Water hyacinth was first introduced into the United States during the 1884 Cotton States Exposition in New Orleans. The plants were given as gifts to attendees, who later took them home to add to backyard ponds. By 1900, water hyacinths had escaped cultivation and become a serious pest. Today, water hyacinth occurs throughout the southeastern states, north to Virginia and west to Texas, and in California and Hawaii. Seasonal escapes from cultivation have been reported from New York, Kentucky, Tennessee and Missouri, but populations did not survive through the winter. The plant previously occurred in Arizona, Arkansas, and Washington State but is now considered eradicated in these locations. Water hyacinth is able to grow in a wide variety of water bodies from lakes, streams, ponds, waterways, ditches, and backwater areas, although it prefers, and grows most prolifically, in nutrient-enriched waters.
See the current distribution of water hyacinth in the United States
Why is Water Hyacinth harmful?
Water hyacinth is considered invasive throughout the world because it grows rapidly and can form thick layers over the water. These mats shade out the other aquatic plants. Eventually these shaded plants die and decay. The decaying process depletes the amount of dissolved oxygen in the water. As oxygen levels decline, many fish are unable to survive. Often the waters below water hyacinth masses become devoid of life.
After establishing in Africa’s Lake Victoria in 1989, water hyacinth eventually grew to cover approximately 77 square miles of the water body.
Dense plant mats also interfere with boat navigation and prevent fishing, swimming, and other recreational activities. Water hyacinth may also clog intake pipes used for drinking water, hydro power, or irrigation. Because the large plants have ample surface area, lake water levels may decrease due to evapo-transpiration, when water evaporates from the lake surface and is lost through plant leaves as vapor. Globally, water hyacinth is considered a serious threat to biodiversity and human health, creating prime habitat for mosquitoes which carry a variety of infectious diseases including Eastern Equine Encephalitis Virus (“triple E”) and West Nile Virus.
Guide to Water Hyacinths (Beautiful Aquatic Plants)
FAQ
Where do you plant water hyacinths?
Container Grown Water Hyacinths
The plants need full sun in garden ponds, but in containers they do best if they have shade from mid to late afternoon.
Do water hyacinths come back every year?
Water hyacinth produces thousands of seeds each year, which can remain viable for up to 30 years.
How do you grow water hyacinth?
Water hyacinth do best in full sun and warm temperatures. Be advised that they’re invasive and will need to be thinned from time to time. Since they’re floating plants, all you need to do is remove a batch from your pond. The roots can get thick so you might need scissors to cut the plants apart.
Does water hyacinth need soil?
Choosing the right base for your Water Hyacinth’s soil mix is like picking a foundation for a house—it needs to be stable and suitable for the living conditions. Opt for an aquatic plant-specific potting mix that’s heavy enough to sink in water, avoiding lighter, floaty materials like peat or excessive compost.