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Eliminating Undesirable Aquatic Plants

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" We came across this article and just wanted repost it. It has a lot of great information on cattails and other unwanted pond and lake plants."

Summertime is here with plant life in full bloom! Plant enthusiasts scurry to tend and coax their flower beds, gardens and green landscaping into dense, lush growths to be admired by all.

Dense, “lush” plant growth in backyard ponds and water gardens!?!?! Well, that’s another story. Tending and coaxing normally becomes pulling, ripping, raking and treating. Granted that many water garden fans passionately grow beautiful, often potted, aquatic plants alongside and within their water features, but most pond owners battle for control of their water against nuisance aquatic plants throughout the growing season. In this article, we’ll talk about two aquatic plants that are very different from one another, yet are nearly equal in stubbornness towards their eradication: Cattails & Duckweed.

Cattail (Typha spp.)

Everyone can recognize the cattail, which is one of the most common emergent weeds throughout the United States. Emergent aquatic plants grow above the water in shallow areas of pools, lakes, ditches and rivers. Many emergent plants are not dependant upon standing water, requiring only saturated soil to thrive. Cattails will grow in moisture conditions ranging from saturated soil to water up to four feet deep. Left unattended, cattails can thickly populate up to 100% of a pond’s littoral zone (shore margin).


If cattails are not desired at your pond, be aware that full control is difficult, but not impossible. Literature describing control of cattails can be confusing as there are differing recommendations. Treatment in spring vs. summer vs. fall? Cutting stems vs. not cutting stems? Cutting back the growth before treatment … after treatment? It certainly can be bewildering. The key to full control of most aquatic plants is to kill the root system. Failure to accomplish this normally results with the quick return of the undesirable plant.

One of the best aquatic plant herbicides to eradicate cattails is “Shore-Klear” (53.8% isopropylamine salt of glyphosphate as active ingredient). Shore-Klear is available in one quart containers. “AquaNeat” (same active ingredient) is available in 2.5 gallon containers for large pond and lake owners. There are basically no restrictions for Shore-Klear usage. Check the label for information concerning distances allowed from potable water intake. It’s always a good idea to also check with your state’s Conservation or Natural Resources department for their restrictions. Shore-Klear is a non-selective herbicide so it will harm your lawn and other desirable plants, so be careful … spray only on a windless day to avoid drift.

Aquatic herbicide applicators recommend the following steps for controlling cattail:

  • Do not treat in the spring.
  • Treat in early fall when the cattail “fruit” is fully grown, but has not yet gone to seed. Everyone is familiar with cattail seeds blowing in the wind by the billions.
  • Treat in the morning of a clear, calm, sunny day (maximum plant activity!).
  • In a simple two or three gallon hand sprayer, or a larger backpack sprayer, mix Shore-Klear with a wetting agent (surfactant) like Cygnet Plus. They are safe and fully biodegradable. Surfactants break down the waxy coating on the foliage and helps the chemical “stick” better.
  • Application rate: Three ounces of Shore-Klear plus two ounces of surfactant per gallon of water.
  • Spray directly onto foliage.
  • Be patient … cattail is a difficult plant and eradication takes time … sometimes two or three fall seasons are required for full control.
  • Always consult the label on the product for exact application instructions and use restriction information.
  • Be sure to consult local authorities for rules and permit requirements for use of aquatic herbicides.

In the meantime, and since you should wait until early Fall to treat anyway ... pull up a few handfuls of young cattail root this Summer … the roots have a flavor similar to celery!

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