They hope to control it by introducing an insect that feeds on it.
https://www.reuters.com/business/environment/south-african-scientists-use-bugs-war-against-water-hyacinth-weed-2023-03-01/?fbclid=IwAR31mNkfZDm9qB051g66KxIvx13Qzcttu-atNznZ73eibETKRq-Db2LnyPk