How should you control cattails growing in a large drainage canal that contains water most of the year?

Controlling cattails in a large drainage canal that is perpetually wet can be quite challenging due to their ability to thrive in aquatic environments. Cutting below the water level is an effective method as it prevents the plants from re-establishing through their root systems. When cattails are cut above the water level, their roots remain intact, and they can regrow quickly once the disturbance is removed. However, cutting them below the water line significantly limits their capacity to survive, as it removes the photosynthetic parts of the plant while deterring new growth.

Spraying or mowing are less effective options in this scenario. Spraying might not provide complete control, especially if the pesticide does not penetrate or affect the plant adequately when it’s submerged. Mowing is also ineffective because it merely trims the tops and leaves the roots intact, allowing for rapid regrowth. Thus, cutting the cattails below the water level is the most reliable method in controlling their growth effectively in aquatic systems.