Question 1

What is Eichhornia crassipes used for in ayurvedic medicine?

Accepted Answer

In Sri Lankan ayurvedic tradition, Eichhornia crassipes is used for its cooling and anti-inflammatory properties, primarily to address skin conditions, urinary tract complaints, and general inflammation. Preparations are typically made from the leaves and roots. Anyone seeking to use it medicinally should consult a qualified ayurvedic practitioner.

Question 2

Is water hyacinth native to Sri Lanka?

Accepted Answer

Water hyacinth is not native to Sri Lanka. It originates from South America's Amazon basin and was introduced to Asia during the 19th century, largely for ornamental reasons. It has since naturalised across the island's freshwater bodies, from ancient irrigation tanks to coastal lagoons.

Question 3

Why is water hyacinth considered invasive?

Accepted Answer

Eichhornia crassipes grows extremely rapidly, capable of doubling its surface coverage in under two weeks under warm, nutrient-rich conditions. Dense mats block sunlight from submerged plants, reduce dissolved oxygen in the water column, and can disrupt irrigation channels and fisheries. These traits have led to its classification as one of the world's most problematic aquatic weeds.

Question 4

Where in Sri Lanka can I see water hyacinth growing?

Accepted Answer

Water hyacinth is most visible on the ancient irrigation tanks of the North Central Province, particularly around Polonnaruwa and Anuradhapura, and on slow-moving river systems in the wet zone. Wetland boat excursions along rivers like the Madu Ganga in the Southern Province also offer close encounters with the plant.

Question 5

What does the water hyacinth flower look like?

Accepted Answer

The flowers appear as upright spikes carrying multiple lavender or pale purple blooms. Each flower has six petals, with the uppermost petal distinguished by a bright yellow spot ringed in blue or violet. Blooming is typically triggered by cooler temperatures and occurs most prolifically outside the hottest months.

Question 6

Can water hyacinth be used to clean polluted water?

Accepted Answer

Research has confirmed that Eichhornia crassipes can absorb excess nitrogen, phosphorus, and certain heavy metals from water through a process called phytoremediation. This property is being explored in constructed wetlands and wastewater treatment systems. However, controlling the plant's spread remains a challenge when it is used this way.

Question 7

How is water hyacinth different from water lettuce?

Accepted Answer

Water hyacinth (Eichhornia crassipes) has distinctive inflated, spongy petioles that act as floats, and produces showy lavender flower spikes. Water lettuce (Pistia stratiotes) forms a pale green rosette of velvety leaves without conspicuous flowers. Both are floating aquatic plants found in Sri Lankan freshwater habitats, but they belong to entirely different plant families.

Question 8

Is Eichhornia crassipes listed in Sri Lanka's official ayurvedic plant catalogue?

Accepted Answer

Yes. Eichhornia crassipes is formally catalogued as one of Sri Lanka's ayurvedic medicinal plants, recognised by the Department of Ayurveda. This listing acknowledges its traditional therapeutic applications within the island's indigenous medical system, though clinical evidence for many of these uses is still being established through modern research.