Kill the roots of even the most persistent emergent aquatic weeds & grasses. Airmax Shoreline Defense is great for controlling cattails or any other plant growing above or out of the water. Apply directly to the foliage, allowing it to be absorbed by the weed, killing the roots for long term control. Shoreline Defense is not to be used for submerged weeds. This pond and lake weed control product is perfect for beaches, shorelines or anywhere emergent weeds grow. 32 fl oz treats up to 10,000 sq ft.