Water lilies, Is there a safe and appropriate way to control their spreading in a pond/lake?
Herbicides are non-specific and would kill any fish and wildlife present as well as all plant material. Special permits would be needed. The most effective way to reduce your water lily growth is to dig out the roots and be sure to remove all plant fragments in order to prevent plant reproduction through fragmentation which could make plant beds even more extensive. This information is from Pond Pals at 1 888 766 3725, Hemphills, a pond installation and maintenance company that advertises their services for all aspects of pond maintenance and water lily control that I googled, among others.
Penn State Publication Distribution Center at 814-865-6713 has printed Pond Management and Aquatic Plant Control by Bryan Swistock who will return to his office on Friday, August 9. (814 863 0194). I've been told you would be able to discuss your problem with him.
Please let us know how you have resolved your problem with the nature of water lily proliferation. We're interested.