Seven Most Common Types of Pond Weeds | Invasive Pond Plants

Seven Most Common Types of Pond Weeds | Invasive Pond Plants

Do you have invasive pond weeds in your home pond or water feature? Certain pond weed types can take over a body of water, depleting the nutrients for the fish and other plants and organisms that share the water. 

Keeping control of aggressive pond weeds can be a challenge, but with the right information it’s possible to regain control of your garden pond or lake. In this article, we take a look at the most important common pond weeds to look out for and go over how to manage them. 

Pond weeds Identification by Type

Identifying invasive weeds in your pond can be difficult if you don’t know what you are looking for. Here is a list of the different types of pondweed commonly found in ponds and lakes: 

  • Algae and Chara: Algae is a nuisance that plagues virtually every home water feature, pond, and aquarium. Algae can float freely throughout the pond’s water column, spreading quickly in the right conditions. Chara takes the form of a clumpy submerged weed and can have an unappealing smell. 
  • Emergent Weeds: Rooted along the shoreline with stems and leaves that stand above the surface of the water. 
  • Floating Weeds: Mostly found in the shallow areas where water is still, floating weeds have a stem and root system that hangs beneath the surface. Sometimes, floating weeds can take over an ecosystem, cutting off sunlight from fish and other organisms below. 
  • Submerged Weeds: Weeds that are rooted in the pond bottom and mostly or entirely submerged underwater. Submerged weeds have soft stem and root systems and sway in the water’s currents like grass in the wind. 
  • What are the Most Invasive Pond Weeds?

    Identifying the invasive weeds and pond grass types in your water feature is the first step in getting rid of them. Although they may sometimes look pretty, invasive plants can wreak havoc on an ecosystem, completely depleting other organisms around them of key nutrients. The sooner you can identify the invasive weeds in your pond, the better. 

  • Duckweed: This common pond weed is made up of tiny petals/leaves that float on the surface of the water with roots dangling just below. Duckweed is common in ponds with minimal water flow; it can attract flies and mosquitoes and quickly spread throughout a body of water. 
  • Cattail: One of a few common pond grass types, cattail can be found along the edges of many ponds and lakes. If left unattended they can overtake the banks of the pond, inhibiting access and view of the water. 
  • Milfoil: This pond weed can be found in ponds, lakes, and rivers throughout North America. It is a densely growing submerged pond weed that can overtake the pond bottom. While it does provide good habitat for fish, milfoil can sometimes grow so dense that virtually no other aquatic plants can root in the pond. 
  • Hydrilla: This grassy pond weed can be found in ponds and lakes across the country. It’s notorious for clogging waterflows and filtration systems, often disturbing the water circulation in the pond. 
  • Clasping-Leaf Pondweed: Growing most abundantly in Canada and the upper United States, clasping-leaf pondweed will often grow until it spans the entire pond. It’s a submergent species that provides regular habitat for fish, turtles, and tadpoles. 
  • Water Lily: While it can look beautiful in the right doses, white water lily can cause a multitude of problems when left to its own. Water lily will bloom vibrant flowers, but they are weeds all the same. 
  • Coontail: Growing below the surface of the water, this submerged pond weed floats freely in the water column. Like many submerged weeds, coontail does contribute to fish and other aquatic habitat’s, but will overrun a pond in a hurry. 
  • Another important weed to mention and perhaps the most common pond weed is algae. We’ve mentioned algae as a pond weed type already, but it’s important to dive a little further here. Algae blooms happen according to a variety of factors, including sunlight, nutrient content, water flow, and water temperature. Often times, adding other aquatic plants to the pond can help balance oxygen levels in the water enough to knock down the algae and clear the water. 

    How to Get Rid of Pond Weeds 

    The necessary removal method will largely be predicated by the type of pond weed you need removed. Floating pond weeds can normally be removed with a rake or by hand. If they are rooted submerged or emergent pond weeds, you may need to cut them at the root to remove them. Certain pond grass types can be removed entirely by hand, by pulling the plant and root system out of the ground. 

    Of course, herbicides and algaecides can also be used to terminate invasive pond species. Just keep in mind that the harmful chemical used in these products can often harm other plants and organisms in the pond. 

    How to Prevent Pond Weeds 

    Preventing pond weeds has much to do with controlling nutrient levels in the water. For the most part, you will want to increase the oxygen in the water while decreasing nutrients like nitrogen and phosphate. To oxygenate the water, many pond owners choose to introduce oxygenating pond plants. Here are a few popular species: 

    • Fanwort: Best suited for depths of three to eight feet. Likes to root in soft, muddy soil and drift freely in the water column above. 
    • Arrowhead: This is an emergent pond species that’s appreciated as much for its beauty as its contribution to oxygen supply. 
    • Water Lettuce: While it too can sometimes be an aggressive weed, water lettuce does make for a great oxygenator pond plant. It is a free floating plant with a submerged root system underneath. 
    • Eelgrass: This flowy submerged grass adds beauty to any water landscape and helps to balance oxygen levels in the soil. It also makes great fish and crawdad habitat. 

    What are the different types of pond plankton? 

    Identifying the plankton/algae species in your pond can help you treat it, but most plankton problems can be controlled by oxygenating the water properly. Some of the most common types of pond plankton/algae species include bryozoans, blue-green algae, euglena, and planktonic algae. 

    Which plant is best for a fishpond? 

    There are a few factors you’ll want to consider if you are introducing pond plants for the sake of fish or other wildlife. Fish require ample shelter from predators, not to mention a place to hunker down and collect food. For this reason, there are a number of free-floating, submerged, and emergent aquatic plants that all serve fish well. A few popular pond plant species to add for fish include hornwort, water lily, fanwort, and watercress. 

    Final Words on Pond Weeds 

    At the end of the day, there are dozens of different pond plant species all capable of overtaking an ecosystem. Most problems arise when a species is left unattended to for too long, or when nutrient balance is off. 

    Solutions to invasive pond weed instances will vary from pond to pond. Some free floating and submerged pond weeds can simply be raked away. Others must be completely uprooted and ripped out. It’s also important for pond owners and property managers to keep in mind the importance of ecological balance. Sometimes, simply introducing a few new oxygenating pond plants or an aerator can help bring a pond back to having clean and clear water.
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