Hydrilla has long, leafy stems that branch and form thick floating mats. The flowering Hydrilla has small white flowers,less than 1/4 inch wide. The leaves have sharply toothed margins and the plant is rough to touch mainly because of the 1 - 12 small sharp teeth or spines that occur on the lower midrib of the leaves. Leaves occur in whorls of 3 to 8.
South Carolina Law requires individuals to possess a Commercial Pesticide Applicators License in Category 5, Aquatic Pest Control, before they apply aquatic herbicides if the work is done for compensation on the property of another. A license is also required, regardless of ownership, if the application is made to an area where public access to the treated site is expected. Private swimming lakes, where the public would exposed to the treated waters, are the most obvious example of the latter requirement. On all public facilities, such as golf courses, driving ranges, subdivisions, condominium/apartment complexes and mobile home parks, applicators are required to possess a Category 5 License to apply aquatic pesticides.