-Written by Aquatic Biologist / Outside Sales, Liz Edgerton
As water temperatures begin to rise through the spring and into the summer months, aquatic plants will begin to grow. Aquatic plants are beneficial to your ponds inhabitants, though too much growth can be an issue and some non-native aquatic plants can become a serious headache if they find their way into your pond. Understanding the types of plants growing in your pond can be helpful in deciding if and how to manage them. Let’s take a look at the three main categories of aquatic plants: submerged, erect, and free floating.
Submerged Aquatic Weeds
Submerged plants are rooted in the pond bottom and grow up through the water column. Submerged plants are usually found in water less than 10 feet deep, but some species can grow at depths of up to 20 feet. Juvenile fish like young bluegill and smaller fish species like minnows use stands of submerged plants as cover to hide from predators. Additionally, submerged plants can help to add dissolved oxygen to the water which is an important part of maintaining a healthy pond. While some submerged plant growth is a good thing, if the growth becomes too dense fish may avoid the area, water flow will become restricted, and dissolved oxygen levels drop, resulting in anoxic conditions. Common submerged plants in the United States include eelgrass, elodea, and American pondweed. Non-native species include hydrilla and parrotfeather milfoil. These non-natives grow very rapidly and can completely fill a pond from top to bottom if not managed.
Emergents Aquatic Weeds
Like submerged plants, emergents are rooted in the pond bottom, however these species extend above the surface of the water. This category includes floating emergents, plants which float on the water’s surface and are rooted in the pond bottom, and erect emergents that grow through the water column and extend straight out of the water. These plants are often found in wetlands and along the shoreline, typically growing in water up to 4 or 5 feet deep. Bulrushes and cattails are common erect emergent aquatic plants, and water lilies are common floating emergents. Many emergents flower and can be a nice addition to your pond, but too many of them could cause problems with accessing your pond by foot or by boat.
Free Floating Aquatic Weeds
Free floating plants live on the water’s surface, are not rooted in the soil, and are usually found in areas with little to no water movement. Duckweed and watermeal are common free floating plant species, while water hyacinth and giant salvinia are fast growing non-natives. These plants are good habitat for insects which in turn provide food for the fish in your pond, however this is also habitat for unwanted pests like mosquitoes. Since these plants are not anchored in the soil, it is possible to control them simply by moving the water. Kasco offers a variety of options for water movement and circulation, including diffused aerators and circulators.
Aquatic vegetation is an important part of your pond that can add aesthetic value and help maintain your ponds ecosystem, though management may be necessary. Overgrowth of native species or the presence of non-native species can reduce fish habitat, lead to anoxic conditions, and limit boat and foot access.
Contact one of Kasco’s knowledgeable biologists or technical specialists for more information by calling 715-262-4488 or emailing firstname.lastname@example.org.