Eichhornia crassipes “Water Hyacinth”

Eichhornia crassipes “Water Hyacinth”

Common Name: Water Hyacinth or Common Water Hyacinth

Named for: 19th century Prussian politician Johann Albrecht Friedrich Eichhorn (1779-1856). He was the minister for education and public welfare.

Family: Pontederiaceae (Pickerelweed family):Members of this family are mainly tropical perennial aquatic herbs found in freshwater. The pickerelweeds (Pontederia) range north into temperate regions, including most of the Eastern United States and Canada.

Distribution: Originally from South America. This plant has been introduced all over the world and has become a major pest. Introduced to Central America, North America (California and southern states), Africa, India, Asia, Australia, and New Zealand.

Description: The plants can vary in size from about an inch to over 3 feet in height. The thick glossy green leaf blades can be up to 1 foot long and 6” across. Generally speaking, the plant does not reach these sizes in cooler areas. Water hyacinth leaves are attached to petioles that are often spongy and inflated. There are many fibrous feathery looking roots which trail in the water from the underside of the plant. The inflorescence is a spike with pretty light-blue to violet flowers. There can be 8-15 flowers for each inflorescence. Each spike can grow up to a foot. Each flower has 6 bluish-purple petals joined at the base to form a short tube. One petal bears a yellow spot. These flowers last only one day.

Care: Water hyacinth is not winter hardy. It does best at temperatures ranging from 25-30C (77-86F). The minimum temperature needed to keep it is 12C (54F). It does not do well at this temperature.

Habitat: Water hyacinths can grow over a wide diversity of water areas such as lakes, streams, ponds, waterways, ditches, and backwater areas. Water hyacinths acquire their nutrients directly from the water. As such, they have been used in wastewater treatment facilities. They prefer and grow most prolifically in nutrient rich waters. Due to the nature of their reproduction they are highly productive. Wind and currents help contribute to their wide distribution. Water hyacinth forms dense rafts in the water and mud. The feathery root system of E. crassipes provides nesting habitat for fish, invertebrates and insects.

Reproduction: Water hyacinth can reproduce sexually by seeds and vegetatively by budding and stolon production. Daughter plants sprout from the stolons. It does not take this plant long to double its size in optimal conditions (6-18 days). The seeds can germinate in a few days or they can remain dormant for up to 15-20 years. They usually sink and remain dormant until periods of stress (droughts). When water is available to them again after a drought, the seeds often germinate. It seems that the majority of the reproduction of water hyacinth is by creating daughter plants. This is where the problems with this plant come into play. A large concentration of these plants create a mat of vegetation. These mats exclude everything else. When the plants reach ‘plague’ proportions, the mats can impede water flow, and create areas for mosquitoes to reproduce. The water under these mats become low in oxygen making it difficult for fish to survive in some areas. Areas of these mats become impenetrable to boats and other forms of water recreation. The removal of these plants from waterways is a major cost to many countries. “Eichhornia crassipes, water hyacinth, is believed to have been introduced into the U.S. in 1884 at an exposition in New Orleans; within 70 years of reaching Florida, the plant covered 126,000 acres of waterways (Schmitz et al. 1993)”
Water hyacinth is not considered a pest here (Canada) since it dies in the winter. Therefore, we can appreciate the beauty of the plant and not be quite so concerned about accidental escapes into the native habitat. We purchased two healthy looking plants from a specialist pond store as the ones in the pet stores looked messy (brown spots and some melting leaves). We gave one away to my father for Father's Day. The other we placed into our small pond in the backyard. The pond is a preformed pond, of approximately 150 gallons. We do not have a filter on the pond. To keep mosquitoes and other water pests at bay, we keep fish in the pond as well. This year we have some Florida Flagfish and Sailfin Mollies. We keep an assortment of plants in there as well as Eichhornia. We also keep a hardy water lily (Nymphaea 'Laydekeri Lilacea'),
Corkscrew Rush (Juncus effusus 'spiralis'), Sarracenia sp. (pitcher plant), Louisiana Iris (Iris lacustris) (collected locally) and native Arrowhead (Sagittaria latifolia) (also collected locally).

The water hyacinth didn't really do much at the beginning as the pond is only in direct light during the morning hours. After almost a month, the plant began to propagate itself with daughter plants. As of writing this article, there are approximately 20 water hyacinth plants in the pond. Several of those plants have also flowered. I wish the flowers lasted longer since they are so pretty. This particular plant has a delicate purple colour, with the one petal having a pretty yellow spot in it. The yellow spot was surrounded by blue.

View of flowering Eichhornia crassipes (Water Hyacinth) in our pond.

There is another benefit to this plant if it does try to take over your pond. It's very good at removing nitrates from your pond, and as such when you remove it, you are removing the nitrates the plant has "sucked" up from the water. The excess plant that you remove is great in compost heaps and will break down easily. If you do keep this plant in a pond with fish, remember that goldfish and koi will eat the roots if they access to them and this will retard the plants growth and may even kill the plant.

Overall, I would recommend this plant to anyone with a pond, as long as they are in an area where they do not have to worry about accidental introductions to the native environment.