Eichhornia azurea, the anchored water hyacinth, is a very attractive waterplant, which is mainly kept due to its very extravagant submersed form. It is widely spread in the American tropics and subtropics, from the South of the USA to Argentine. It forms dense floating carpets of several metre-long shoots with emersed spoon-shaped leaves and beautiful white, purple or azure blue flowers on stagnant and flowing waters. The submersed form is quite rare in the natural habitat, though. Its lineal, light green, soft leaves grow in double rows on the stem, reminding the onlooker of a palm leaf. However, if submersed shoots reach the water surface they don’t take long to assume their emersed form and develop long-stalked, spoon-shaped shining aerial leaves. The stalks of these leaves contain spongiform tissue, which serves as buoy, however, different from those of the water hyacinth Eichhornia crassipes, they don’t form bulbs.
Groups of E. azurea can be frequently found in large aquaria. This kind of planting is not without difficulties, however, as the submersed shoots grow to a width of at least 20 cm, and thus need lots of room, and because the very fragile submersed leaves must not be squeezed when they are planted, or else they turn blackish. The plant can be far better integrated into a design as a solitaire. When used this way it forms a beatiful eyecatcher with its stunning palm-leaf-like habit.
Propagation is easily done by head cuttings. On the remaining stem, 2 to 4 lateral shoots form after a few days, which in turn can be used as cuttings, too. If you want the number of stems to remain the same, remove the lower part of the stem and plant the head cutting in its place.
E. azurea is most suitable for tanks with a height of 50 cm and over as it has a tendency to grow strongly towards the surface and thus has to be cut back and re-planted quite often. High tanks are recommendable for another reason, too: When the plant reaches the water surface it starts growing along it and develops its spoon-shaped floating leaves very soon. The top of such a shoot is lost for submersed cultivation. If it is cut off and re-planted the plant will continue to sprout emersed leaves. It does not change back into the submersed form. Thus the keeper has to have a close eye on these plants to prevent them from reaching the surface. However, not all is lost if you missed a shoot, as you can regain the submersed form. Cut off the emersed shoot pretty low (around 10 cm above the ground) and leave the stump. It will throw new submersed lateral shoots you can use as cuttings.
Eichhornia azurea needs ample amounts of nutrients, or the leaves (which are susceptible to pressure anyway) tend to turn blackish at the bottom.
The floating form is quite spectacular in large open tanks as it will grow beautiful flowers.