How to control Duckweed

What Type of Duckweed Do I have in my pond?

There are three common types of duckweed in North America. Common Duckweed, Giant Duckweed and Dotted Duckweed.

Where Can Duckweed Grow?

Duckweed can be found in ponds, lakes and streams.

What is Common Duckweed?

Where Does it Grow?

Duckweed grows in dense colonies in quiet water, undisturbed by wave action. Usually there is more than one species of duckweed inhabiting a body of water.

Is it invasive?

Duckweed normally is an aggressive intruder of ponds and are often found mixed in with other unwanted weeds. If masses of duckweed cover the surface of the water, then oxygen is depleted and fish kills will most likely occur. Therefore it is necessary to get control before they completely cover the surface of the pond.

Pros and Cons of Duckweed

Submerged parts of all aquatic plants offer habitats for several species of invertebrates. These invertebrates are then used as food by fish and other wildlife species (e.g. amphibians, reptiles, ducks, etc.). When the duckweed dies off, their decomposition by bacterium and fungi provides food (called “detritus”) for several aquatic invertebrates.

What is Dotted Duckweed?

Where Does it Grow?

Dotted duckweed is non-native and can be found in rivers, ponds and lakes.

Is it Invasive?

The Dotted duckweed is usually an aggressive invader of ponds and are often found growing with other duckweeds, mosquito fern, and/or watermeal. If these groups of duckweed cover the surface of the water, then oxygen depletion and fish kills can occur. These plants need to be controlled before they cover the whole surface of the pond.

What is Giant Duckweed?

Where Does it Grow?

The Giant Duckweed grows in ponds, lakes, bayous, and sluggish streams. Often more than one type of duckweed will grow together in these colonies.

Is it Invasive?

Although the giant duckweed is a native weed, it can be an aggressive invader of ponds and are often found mixed in with other duckweeds, mosquito fern, and/or watermeal. If this group of aquatic weeds cover the surface of the water, then the oxygen in the pond depletes and fish kills can occur. These plants need to be controlled before they move over the entire surface of the pond.

Pros and Cons of Giant Duckweed

Many types of ducks consume duckweed and frequently transport it to other bodies of water. Thick duckweed colonies offer habitats for many species of invertebrates, but if duckweed completely covers the surface of a pond for an extended period, it will cause oxygen depletion. These colonies will also eliminate submerged plants by hindering sunlight penetration.

How to CONTROL Duckweed

One method is by using a lake rake to rake it off the pond's surface.

Duckweed as well as other forms of aquatic weeds prefer stagnant water environment. Adding a pond aerator puts oxygen back in the pond and will get rid of Duckweed and prevent it from coming back.

Ducks will eat duckweed but they will not control it.

Beneficial Bacteria

BactiMAX+ will remove ammonia, nitrite, nitrate, and organic debris (dead leaves, uneaten fish food, fish waste, etc.) the ingredients that aquatic weeds need to thrive.

• ·         Bacillus amyloliquefaciens. Degrades starches and carbohydrates
• ·      Bacillus subtilis. Degrades starches, proteins, and fats
• ·      Bacillus licheniformis. Converts nitrate to nitrogen gas
• ·      Cellulomonas biazotea. Digests cellulose