Water hyacinths are able to survive the winter through USDA plant hardiness zones 8 through 11. In other parts of the country, you'll need to provide water that's at least 70 degrees and provide 12 hours of sunlight each day. This will require an aquarium, a heater, and a strong grow light.
In places where water hyacinth are able to survive the winter, they may turn brown and their leaves may die as things get colder. However, as things warm back up, the plant will reemerge and sometimes even grow new daughter plants from spreading stems.
