Many of us think that it is so invasive. It is good looking plant with beautiful flower. It is invasive in that sense, it pollutes the water. It can pollinated through bees or self clone and grow rapidly and quickly cover the surface of water and that lead to slow down the flow of water and show detrimental to fish. The decaying plant matter that sink down reduce the oxygen available and killing the fish,turtles and other aquatic life. That also blocks for native plant of water causing them to die.
It is one of the fastest growing plant and have super long roots( that absorb tons of nutrient so act as water purifier), provide wonderful spawing mop for fish. It can also be used as food sources in some country and as composting source for agriculture. Because of its amazing biomass it can be used to create fuels. When it flowers it sends up a single spike that can gets a bunch of really beautiful light purple flower. So it can also be used as water garden pond.
Those who choose to enjoy water hyacinth in their water garden ponds should be careful on how they use them and have to mantain the area of the plant as it is super fast growing plant and quickly cover the surface of water.