Q: How do I know which chemicals will treat my weeds?
Henry – Markesan, WI
A: Weeds. Whether they’re algae or submerged, floating or shoreline plants, they’re a nuisance—not to mention a potential hazard to your game fish and pond or lake health. In order to manage these green invaders, you should get to know them a little better. Don’t worry: you don’t need to be a Master Gardener to identify and treat them. Here’s all you need to know:
1. Know the Weeds
Before you start dumping chemicals on the weeds in your pond, you’ll first need to understand the different types of aquatic weeds that pop up in lakes or ponds. There are four basic categories:
- Algae. Algae comes in three basic types: Planktonic, which causes the pea soup look in your water; filamentous, which creates blankets of stringy stuff or pond scum; and chara or muskgrass, which smells like musky garlic. When you take a closer look, these weeds have no defined root systems, unlike their other weed cousins.
- Submerged. Submerged weeds live underwater. This group of troublemakers includes bladderwort, several types of pondweed, watermilfoil, parrot feather and hydrilla. They look like a typical plant, with leaves, stems and root systems.
- Floating. Floating weeds generally reside in shallow water and have root systems that reach into the water or down into the soil, allowing their leaves and flowers to rise to the surface. They include watermeal, duckweed, azolla and even water lilies. When not kept in check, these floaters can take over a pond in no time.
- Emergent. Emergent weeds live along your lake’s shoreline. These plants like to keep their feet wet; their foliage, leaves and flowers live out of water, but their root systems prefer wet, almost completely saturated soil. Emergent weeds include cattails, phragmites, purple loosestrife and bulrush.
2. ID the Weed
Once you identify the category of weed you’re dealing with, head over to our Weed Control Guide and try to match weed with the picture. For example, is it a floating plant with a root system? Then you’re dealing with a type of floating weed. Is it completely submerged? Then you’re dealing with a type of submerged weed.
Each weed included in our Weed Control Guide will describe the best treatment options to manage it. Not sure of the weed? Snap a close-up photo and e-mail it to us at firstname.lastname@example.org. Of course, you can always call us toll-free for advice, too, at 866-POND-HELP (766-3435)!
3. Treat the Weed
Once you’ve ID’d the weed, treat it with its appropriate herbicide, remembering to always follow label instructions when applying it to your pond or lake. If you have fish in your pond, we suggest treating in sections as sudden changes in water conditions can affect aquatic species. Treat 1/4 – 1/2 of pond at a time, while waiting 10-14 days between treatments.
4. Remove the Remains
Once the chemicals start working to kill the weeds, make sure you remove the decomposing foliage with a weed rake, like the Jenlis WeedRazer® Aquatic Weed Cutter. Why? Because anything dead will turn into muck and start the weed/algae cycle again—which is not something you want to happen, right?
Pond Talk: What tips do you have for managing aquatic weeds?