Cattails (Typha latifolia), common fixtures in the wetlands and lily ponds of U.S. Department of Agriculture plant hardiness zones 2 through 11, grow and spread vigorously, often forming stands that overtake small bodies of water. You can remove cattails from a lily pond mechanically or chemically, with the latter method requiring far less labor than the former. However, when controlling cattails using chemical means, you must use an herbicide approved for aquatic applications, such as glyphosate. Unlike contact herbicides, aquatic-use glyphosate acts systemically, travelling through the thick, waxy exterior of the cattail and penetrating its root system.
Wade into the pond and grasp the cattails where they emerge from the pond floor after new green growth extends 6 inches above the water surface. Pull the cattails from the pond floor, uprooting as much of the root system as you can. Use the cattails for compost or discard them.
Wade into the pond and trim back the cattails’ green growth to water level using garden shears after it emerges from the pond. Killing the cattails by topping them off to water level can take years before the root systems die.
Mix together an herbicide labelled for aquatic use containing the active ingredient glyphosate with the manufacturer’s recommended amount of water just after the seed heads form at the tips of the cattails. Add a non-ionic surfactant labelled for aquatic use to the diluted glyphosate and mix well. Pour the glyphosate in a compression-tank type sprayer and stand at the edge of the pond. Spray the herbicide liberally on the portions of the cattails you can reach. Wait at least two weeks for the cattails to die.
Things You Will Need
- Garden shears
- Aquatic-use herbicide containing glyphosate
- Aquatic-use surfactant
- Backpack sprayer
- Follow the manufacturer's instructions when diluting glyphosate with water and surfactant; as concentrations of both may vary.
- Wear protective gloves, protective eyewear, long sleeves and long pants when mixing and applying herbicide.
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