Managing unwanted aquatic plant growth (pond weeds) in a lake or pond usually boils down to reducing and managing the amount of organic nutrients contained in the water. Herbicides give quick results but the effects do not last long because the root cause remains while only the symptom of heavy growth was temporarily diminished. The typical watershed includes manicured urban lawns and agricultural land actively in use. Urban lawns have pesticides and fertilizers applied to them at ever increasing levels as people chase the idea of a lush lawn the perfect shade of green. The relatively short and shallow rooted turf grass cannot absorb all the nutrients from the fertilizer and does nothing to hold back sediments as rain easily flushes both downstream into the pond. Agricultural land also has fertilizer use but at a very controlled rate as the farmer only wants to spend enough money to get the amount needed to the crops. A few feet below the surface lies a tile used to keep the land dry enough to use large equipment on to plant, maintain and then harvest those plants. In the short distance from the surface to the tile not all of the nutrients can be cleared. Once the water hits the tile, no more nutrients are removed as the water is transported to the nearest stream and pond. All of this leads to nutrient rich ponds with ever increasing levels of aquatic plant growth.
There are techniques to reduce and control the nutrients in the lake and pond and the best use nature to do the work. Floating islands are a manufactured platform that floats on the surface of the water supporting native wetland plants and natural bacteria which both digest and sequester nitrates and phosphates in the water that other aquatic plants use to grow. Getting this natural system is easy and quick. The islands come with preformed areas the size of a small pot that are filled with a small bit of soil and a plant plug bought locally. Wetland plants native to your area are best as they are adept at surviving the local conditions and contribute to the natural environment. The small amount of soil in the preformed pots give the young plant plugs a jump start to get growing.
As the wetland plants continue to grow, the roots extend into and then through the matrix of the island hanging out the bottom in the water. The roots then pull everything they need from the water column which includes the nutrients nitrates and phosphates. Natural bacteria already growing in the water and bottom composition of the pond take advantage of the island to grow both in the matrix and the root mass hanging below. Overall, the natural bacteria growth levels and activity are increased in the lake or pond which pulls even more nutrients from the water column. The end result is a lake or pond with improved water quality. As the nutrients are reduced and controlled, aquatic plant growth typically declines as they have less energy sources to utilize. Aquatic plants are important for the ecosystem and some will still remain in the pond but at the desired levels. Occasional spikes in growth from water events are still possible, but the extent and duration of the increase should be lessened.
Not only do the floating islands improve the water quality but they also add to the habitat. Above the water, the plants, flowers and seeds give birds, butterflies, turtles and other animals places to live and food sources. Below the water, the matrix of the island and the roots hanging in the water are shady places for insects, phytoplankton, zooplankton and other small creatures a place to find refuge and food. This sets up a localized food chain attracting the large predators of the pond which are typically bluegill, bass and catfish. Where there used to be open water devoid of life, an entire ecosystem now exists.
As you can see, floating islands benefit the environment in many ways. They replace wetlands that used to filter and clean the water that we removed to plant crops and build houses. In doing so, the floating islands take remediate the overabundant aquatic plant growth that we find unsightly, foul smelling and at times hazardous to our health. They improve the environment using natural processes and add to the habitat of the ecosystem. Floating islands are a great lake and pond management option that you should consider.