Pondweed Control: How To Get Rid of Pondweed

Pondweed is the broad name given to 80 or so species of aquatic plants belonging to the genus Potamogeton. One of the most common of them in this country is known as the American Pondweed. American Pondweed is a perennial plant that has both floating and submerged leaves which create a pattern where both types of leaves alternate.

American Pondweed is a beneficial part of the ecosystem where it grows as their leaves are a food for ducks and other kinds of wildlife. However, when they are growing in heavy numbers, it can make for an ugly sight. Pondweed is a threat because it has a tendency to outcompete native plants and form dense mats that block the sunlight these plants need to grow.

If you have Pondweed plaguing your pond or lake, we can help. Our DIY guide below was put together by our experienced aquatic weed specialists and contains the best product recommendations and know-how for you to successfully remove this invasive weed from your pond.

Identification

Pondweed has floating leaves that are oval-shaped and range between 4 to 7 inches long and 1 to 2 inches wide on long petioles. Leaves that are submerged in the water are few in number and are blade shaped and smaller than the ones that float around. American Pondweed bears fruit which is set on spikes that often stand above the water's surface. They are brownish to reddish in color, 2 to 3 inches long and 1/8 to 1/4 inches wide.

Use the following description and the corresponding image to help you to identify pondweed. If you need more help, contact us and we will help you to identify the algae you have.

Inspection

It is important to conduct a careful inspection and analysis of the body of water that will be treated for Pondweed. Take into account the fishes and aquatic life that use the body of water as a habitat as well as the other vegetation in the water that is desirable and vital to the ecosystem before applying chemicals. Walk by your water body and observe the water to check for pondweed and to determine how big of an outbreak you have.

Where to Inspect

Pondweed can appear in lakes, ponds, ditches, streams and shallow water; it also found commonly in rapid and deep waters. Walk around your pond to observe the water or take a boat out to get a closer look.

What to Look For

Pondweed can be easy to find. Look out for their floating leaves and their brownish-red seedheads which will jut out above the water.

Treatment

Before handling any chemicals it is essential to first put on the proper personal protective equipment (PPE) for safety such as gloves, long-sleeve shirt, long-sleeve pants, closed-toe shoes with socks, glasses, and mask.

Our top recommended products to treat pondweed is Diquat Herbicide. Diquat Herbicide is labeled to control Pondweed (except for Richardsons pondweed) and has shown to do a great job against it. Diquat also carries a wide label so it can kill a large number of other unwanted aquatic weeds you may be dealing with too.

Step 1 - Prepare and Mix the Diquat

Before mixing and application, you will need to calculate the size of the water body you wish to treat to determine how much Diquat you will need. For water bodies, the measurement is usually done by calculating the acreage or acre-foot. To do this, measure the length, width, and average depth of the water body in feet then divide by 43,560 (Length (ft.) x Width (ft.) x Average Depth (ft.) / 43,560 = Acre-feet).

According to the label, Diquat should be mixed at a rate of 0.5 to 2.0 gallons of product in water per surface acre (per 4-foot water depth). For severe weed infestations, use the 2.0 gallon per surface acre rate.

Step 2 - Apply Diquat to target Pondweed

Once the Diquat is well-mixed. Depending on the targeted weed and the waters depth, you can spray the herbicide over the water along the shoreline, spot treat emerged weeds, or broadcast spray over the waters surface. Use a fan spray nozzle to ensure an even coating on the water surface.

Step 3 - Follow Up Applications

Depending on the size of your pond or lake, you may need to conduct treatment in sections, waiting 2 weeks between treatments until you've treated the entire body of water. Reapplication may be necessary 21 days after the initial application is complete. Pondweed can be a stubborn weed to remove so monitoring your water is key and repeated application is crucial to get complete control.

Prevention

To keep Pondweed from returning to your water body, we recommend applying Vision Pond Dye. Vision Pond Dye puts a stop to plant development by blocking sunlight into the water and also gives your pond a clean blue color.

Measure the appropriate amount of Vision Pond Dye into a bucket based on your pond area measurement findings. The label recommends applying at a rate of 1 quart per 1 surface acre of water at a 5-foot average depth.

Pour the pond dye over the edge directly into the body of water and the water's natural movement will disperse the dye.

Key Takeaways

• Pondweed is a beneficial plant on water surfaces, but becomes a problem when it grows in abundance.
• Applications of Diquat Herbicide has proven to work best against Pondweed outbreaks.
• Applying Vision Pond Dye after a herbicide application works as a great preventative measure that hinders pondweed growth and enhances the aesthetics of your pond.