What is water hyacinth

Water hyacinth


from 10.00cm to 20.00cm
Growth width
from 20.00cm to 30.00cm
Ornamental or utility value
  • Floral decorations
  • Leaf jewelry


The water hyacinth (Eichhornia crassipes) belongs to the family of the water hyacinth plants (Pontederiaceae) and is originally native to Brazil. If you look closely, you can see the parallel-veined leaf veins that characterize it as a monocot. Thanks to the balloon-shaped petioles, their leaves float on the surface of stagnant or slower flowing waters.

In the meantime, the floating leaf plant has become a plague in its homeland, but also in other tropical regions of Africa and China, because under good growth conditions it displaces native species and overgrows entire bodies of water and overloads them with nutrients. In some regions, this oversupply is used by drying their stems and weaving them into baskets or furniture or using them as green manure. In order to prevent uncontrolled spread in nature, the EU put the water hyacinth on the "List of invasive alien animal and plant species" back in 2016. For this reason, it is no longer allowed to be sold. In our climate it shouldn't be a problem, but under no circumstances should specimens of the water hyacinth be placed in natural waters. A closely related species that is also used as an ornamental plant for garden ponds is the azure water hyacinth (Eichhornia azurea).


The water hyacinth is a floating leaf plant that floats on the surface of the water and quickly forms dense stands under good growth conditions. Their roots can be up to 40 centimeters long and remove many nutrients from the water.


The water hyacinth forms fleshy, fresh green leaves for each inflorescence, which are arranged in leaf rosettes and float on the water. The inflated leaf stalks, which contain an air-filled, spongy tissue, serve as floating bodies.


The light purple flowers of the water hyacinth form a spike-like inflorescence that protrudes from the water. They only develop in warm summers with high humidity from July to September. Each individual flower has a pretty yellow pattern.


The flowers of the water hyacinth produce capsule fruits or nuts after pollination by insects. However, our temperatures are usually not sufficient for this.


The water hyacinth grows in still or very slowly flowing shallow water at a water depth of at least 10 centimeters. The water should warm up quickly, ideally a sunny location and nutrient-rich water. Even in small mini ponds in barrels or vats, the exotic, adapted to tropical conditions, feels at home, as the water in them warms up quickly. The warmer and more humid the summer, the more reliably the showy flowers develop. The very frost-sensitive water hyacinths may only be used from May and should be taken out for the winter at the latest in October.


Since water hyacinths are floating leaf plants that do not anchor themselves in the pond floor, they are simply placed in the desired location in the water from May, when there is no more threat of frost. You calculate about two to three plants per square meter. At first you should be more cautious with the stocking amount and watch how the population develops.


In years with good growth conditions, the water hyacinths may have to be thinned out from time to time so that they do not overgrow the entire pond. To thin out, you simply fish a few specimens out of the water or separate off foothills. The wintering of the tropical water hyacinth is very complex, because it needs a very bright winter quarters with temperatures of at least 15, better 20 degrees Celsius. A shallow bowl, which you fill with loamy soil and water, can be used as a wintering vessel, or you can use an aquarium or a water basin with a minimum water depth of 20 centimeters.

The water hyacinth needs at least 12 hours of light a day, which can only be achieved with additional lighting during the dark season. Temperature fluctuations should be avoided, so a heated winter garden is ideal. Since the water hyacinth does not pause growth under these conditions, it should be regularly supplied with nutrients outside of the water. Use special aquatic plant fertilizers and adhere to the dosage instructions. Only when there is definitely no more frost to be expected can the plants be put back into the pond in May. If wintering is too time-consuming for you or if you don't have suitable options for wintering, you can also grow the exotic aquatic plants as annuals and buy new plants every spring. In this case, you should fish the water hyacinths out of the pond with a landing net in autumn and add them to the compost. This prevents the plants from dying off when exposed to the cold, sinking to the bottom and unnecessarily polluting the water with nutrients.


If the water hyacinth spreads vigorously in good growth conditions, it may be necessary to divide the plants during their growth phase by separating the runners and throw away parts of the plant or give them away to other hobby gardeners.


Like many other aquatic plants, the water hyacinth cleans water from pollutants and nutrients and thus serves as a natural water filter. Due to its densely packed leaves, it shades the area below and prevents excessive algae growth. Because of its striking color and exotic appearance, the water hyacinth can sometimes act as a foreign body in natural ponds, but that is of course up to personal taste. It can be stylishly staged in formal pond basins or wide water channels.


The water hyacinth can easily be propagated using runners. Fruit and seed formation only takes place in the tropics and does not work in our climatic conditions. In order to multiply them, you only have to cut off a branch and then put it back in the desired place. From this an independent plant quickly develops again, which sprouts new runners.

Diseases and pests

Neither is an issue: water hyacinths are neither susceptible to disease nor are they plagued by pests.