How Do I Get Rid of Cattails?
The most effective way to control cattails is a systemic herbicide, such as Clearcast, applied to the exposed foliage during late summer or early fall, when the plant is naturally pulling nutrients down into its root system to store for winter. Spraying at this time carries the herbicide down into the roots along with those stored nutrients, which is what actually stops the plant from regrowing the following season. Cutting or mowing cattails without treating them first typically isn't effective on its own, since the root system is left intact and the plant simply grows back.
Are Cattails Actually Good for a Pond?
In moderation, yes. A modest stand of cattails helps stabilize shoreline soil, filters nutrients and sediment from runoff before it reaches open water, and provides genuine habitat and food for wildlife. The issue isn't cattails existing in a pond, it's cattails left unmanaged. Left to spread, they can take over shallow shoreline areas, crowd out recreational space, alter fish habitat, and speed up the natural aging process of a pond as decaying plant material adds to the muck layer on the bottom.
When Do Cattails Become a Problem?
A cattail stand becomes worth addressing once it starts noticeably narrowing usable shoreline, blocking views or access to the water, or spreading beyond the area it originally occupied. Left unaddressed for multiple seasons, a dense cattail stand can meaningfully reduce a pond's open water space and contribute to the same muck buildup that fuels recurring algae problems, since dead cattail material breaks down the same way any other organic debris does.
What's the Best Time of Year to Treat Cattails?
Late summer through early fall, roughly August through the first frost, is the strongest window. Cattails are mature by this point, giving a spray application more plant surface to absorb the herbicide, and the plant's natural seasonal shift toward storing energy in its root system pulls the treatment down where it does the most good. Spraying too early in the season, while the plant is still focused on above-ground growth, generally produces weaker, less complete results.
What About Phragmites?
Phragmites (common reed) is another aggressive shoreline plant that follows a similar treatment window and approach: a systemic herbicide applied to mature growth in late summer or early fall, allowing the plant's natural nutrient shift to carry the treatment into the root system. If you're dealing with both cattails and Phragmites along the same shoreline, this time of year is the right window to address both in the same pass.
What Herbicide Should You Use on Cattails?
For cattail control, we recommend Clearcast, a systemic herbicide built specifically for cattails and other emergent shoreline vegetation, including Phragmites. Because it's systemic, Clearcast is absorbed through the plant's foliage and carried down into the root system rather than just burning back the visible growth, which is why it holds up better long-term than cutting or mowing alone. It's labeled for use in and around water, making it a fit for pond and shoreline applications where drift and runoff need to be kept to a minimum. Applied during the late-summer-to-fall window, when the plant is already pulling nutrients toward its roots, Clearcast gets carried right along with that process for more complete, longer-lasting control.
How Do You Apply Cattail Herbicide Correctly?
Spray the exposed foliage above the waterline thoroughly, since the herbicide needs enough leaf surface to be absorbed and carried down to the roots. Allow one to two weeks for the herbicide to take full effect, you'll see the plant gradually brown and wilt as it works. A second application may be needed for thick, well-established stands, since a mature root system can be difficult to fully knock out in a single treatment.
What Do You Do After Spraying?
Wait until treated cattails are fully brown and wilted before cutting or removing them, removing green, still-living cattails interrupts the herbicide's work before it's finished reaching the roots. Once dead, cut and rake out the dead foliage rather than leaving it to decompose in the water, since decaying plant material adds directly to the muck layer that feeds next year's algae growth. Removing dead material in fall also gets ahead of spring growth, making it easier to stay in control of the area going into next season.
A Quick Reminder on Applying Clearcast
Always apply Clearcast per label directions, and treat during calm conditions to avoid drift onto desirable shoreline plants. If you're dealing with a thick, well-established stand, plan for the possibility of a second application rather than expecting one pass to fully clear a mature root system.
Not Sure If Your Cattails Need Treatment?
Click the Ask Our Pond Pro button in the bottom right corner of any page on thepondshop.com and describe what you're seeing, how much shoreline is affected, and how long it's been spreading. We'll help you figure out the right approach and timing for your pond.
Call: (800) 527-9420 Email: sales@thepondshop.com
Related Reading from The Pond Shop
- Is It Algae or a Pond Weed? How to Tell the Difference
- Why Pond Muck Causes Algae (and How to Get Rid of It)
- The Importance of Pond Aeration
FAQ
What's the best time of year to get rid of cattails?
Late summer through early fall, roughly August through the first frost, is the strongest window. Cattails are pulling nutrients into their root system to store for winter during this time, which helps carry a systemic herbicide down into the roots for more complete control.
Are cattails bad for my pond?
Not inherently. A modest, contained stand of cattails helps stabilize shoreline soil and provides wildlife habitat. They become a problem when left unmanaged and allowed to spread, crowding out recreational space and contributing to muck buildup as plant material decomposes.
Should I cut cattails before or after treating them?
After. Cut and remove cattails only once they've turned brown and wilted from herbicide treatment, typically one to two weeks after application. Cutting green, living cattails first removes the leaf surface needed to carry herbicide down to the roots.
Will cutting cattails without herbicide get rid of them?
Not permanently. Cutting or mowing alone leaves the root system intact, and cattails typically regrow from the roots the following season without a systemic herbicide treatment.
Does treating cattails also work on Phragmites?
Phragmites responds to a similar approach, a systemic herbicide applied to mature growth in late summer or early fall. If both are present along the same shoreline, this window is a good time to treat both.
