Water lilies are amazing plants. They grow wild but take a huge effort to cultivate in gardens due to the need for a certain type of water feature. There are 70 known species of Nymphaeaceae in the world. I have seen them growing in the Mississippi River and the grow in stagnate ponds all over the tropics and temperate parts of the world. There can also be too much of a good thing. Quoting from Wikipedia: Nymphaeaceae:
The Mexican water lily, native to the Gulf Coast of North America, is planted throughout the continent. It has escaped from cultivation and become invasive in some areas, such as California's San Joaquin Valley. It can infest slow-moving bodies of water and is difficult to eradicate. Populations can be controlled by cutting top growth. Herbicides can also be used to control populations using glyphosate and fluridone.