The water hyacinth and water lettuce are perhaps the two most common floating water plants that can be found growing inside a pond. In Singapore, the duo are a common feature in almost every primary school that has a pond in its ecogarden. I can still vividly remember my primary school teacher mentioning these two plants as examples of a floating pond plant in one of my science lessons.
These two plants are known to be extremely fast-growing when the growing conditions are right and their growth can often get out of hand. In some parts of the world, they have become weeds (or pests) because they choke up the waterways there!
In Singapore, I have seen people who grow these two plants in their garden ponds fishing excess plants out that have overgrown and dumping them into the compost heap to rot away. Others who do not have a compost heap in their garden have instead laid the discarded plants on the ground to serve as a mulch.
These two fast-growing water plants, on the other hand, are essential in a pond ecosystem as a colony of them on the water surface will somewhat help to provide some shade and keep the water cool and the pond’s aquatic inhabitants happy under the glare and heat of the direct tropical sun. However, if left unchecked, these plants can multiply, spread and eventually covering up the entire water surface of the pond.
During a recent visit to a local primary school’s community and eco-garden, I saw a very innovative way that had been devised by the school to contain the spread of water hyacinths and water lettuces so as to prevent them from covering up the entire water surface of a pond. The school made circular boundaries using plastic meshes which were placed inside the shallow pond. Floating water plants are grown inside these circles as shown in the picture below.
By looking at the picture below, we can see how water hyacinths can be contained within one particular zone in the pond.
Upon deeper thinking, the circular boundaries made out of plastic meshes will only work in shallow ponds. The plastic meshes are dense and I presume they do sink if they are used in deeper ponds. However, one may want to consider using plastic hoola hoops in the latter situation. Plastic hoola hooks that I have come across are hollow in the center and these will float when placed on the water surface. These will hence be able to help round up any floating water plants that stray in a deep pond.
