Physically cutting pickerelweed and digging up the roots can be a somewhat successful way to manage this plant. Pickerelweed can re-grow from roots that remain or from seeds left behind.
Imox herbicide and a Surfactant will effectively control pickerelweed. These products together are called our Cattail and Water Lily Control. Thoroughly wetting the plants in late summer or early fall is the most practical time to treat. This is when Pickerelweed Plants are directing their energies to the root system, which helps pull the herbicide down to the roots to kill both those and the vegetative portions.