Coontail lacks true roots, so it may be very loosely anchored to the bottom or float freely. It can grow in deep water (>6 feet) and often stays green and continues to grow throughout the winter. Value and Concern to the Pond Coontail has tremendous value to the pond or lake because it provides food and habitat throughout the year. The dense stems are great habitat for insects and provide a source of food for fish and other wildlife. Waterfowl will feed directly on the plant. Coontail can grow to nuisance levels in ponds and lakes with excessive amounts of nutrients.
Overabundant growth is a symptom of excessive nutrients (phosphorus and nitrogen) in the pond water. These nutrients may come from barnyards, crop fields, septic systems, lawns, and golf courses. Control of coontail is best accomplished by reducing fertilizer applications near the pond, maintaining nearby septic systems, redirecting nutrient-rich runoff away from the pond, and maintaining vegetative buffer strips around the pond.
Coontail does not respond well to cutting, raking, or harvesting because it can reproduce from small plant fragments left behind.
Grass carp can be used to control coontail. Grass carp must be purchased from an approved hatchery after receiving a state permit. Consult the grass carp fact sheet available from your local PA Fish and Boat Commission (PFBC) office or at the Penn State Extension website.
Numerous aquatic herbicides can be used to control coontail, including Aquathol-K, Aqua-Kleen, Komeen, Navigate, Reward, Weedtrine-D, and Sonar. These herbicides and their proper use are further discussed in Management of Aquatic Plants . Make sure that you positively identify the plant in your pond as coontail before proceeding. Carefully measure the pond area and volume to determine the amount of herbicide needed. You must also complete a two-page permit application to apply any aquatic herbicide to a pond or lake in Pennsylvania. Aquatic herbicides can be purchased from home- and farm-supply stores, hardware stores, or various online suppliers. Follow the herbicide label carefully. Herbicide treatments should be done early in the growing season before the plant cover a large portion of the pond. Treatment of severe infestations may cause a fish kill due to reduced dissolved oxygen.
For further information and publications on pond management visit the Penn State Extension website or contact your local extension office.
Prepared by Bryan R. Swistock, senior extension associate and Heather Smiles, fisheries biologist, Pennsylvania Fish and Boat Commission.