Some plants can live in water. They may grow up with their roots in mud or float in the water. They have adapted to be able to get air to their roots by taking it out of the water or sending it down through the stems from leaves that stick out into the air.
Most of the plants in a pond are perennials. It is not a good place for annuals. Most plants also die back in the winter, keeping themselves in relatively warm water and away from frosts.
