Indiana Aquatic Weed Control and Pond Management

Invasive aquatic plant species in Indiana’s waterways are a source of biological pollution that threaten the ecology of the states’ water resources. These resources are at risk when nuisance exotic plant species invade these ecosystems. Below is a guideline for approaching Indiana aquatic weed control along with a list of the more common aquatic weeds found in this great state.

Purple Loosestrife

Purple loosestrife is a perennial that stands erect on a square, woody stem. Each rootstock can have 1 to 50 stems reaching a height of 10 feet. Green leaves sit opposite on the stem and are lance-shaped with smooth edges. This plant puts up many flower spikes and each spike is covered with five to six, pink to purple petals with yellow centers. Annually this plant can produce up to 2 million seeds the size of a grain of sand with 60-70% viability.

Purple loosestrife was first introduced to the east coast of the United States in the 1800’s for ornamental and medicinal uses. By 1940, most of the Midwest was invaded by this exotic and by 1985 it had found its way across the United States to the west coast.

It is estimated that over 1 million acres of U.S. wetlands are taken over by this invader each year. It adapts well to any kind of wetland quickly crowding out native species leading to the displacement of native wildlife. It does not provide adequate cover for wetland animal species nor is it a viable source of food and has become a major problem for Indiana aquatic weed control. For removing Purple Loosestrife from your lake or pond, Lake Restoration recommends an Open Water kit, which is also effective in killing cattails and water lilies.

Eurasian Watermilfoil

Eurasian watermilfoil is a submersed perennial with a long underwater stem that branches profusely at the surface of the water. The plants leaves are whorled (opposite) on the stem at each node with four feather-like leaves per whorl. It produces small reddish flowers that emerge several inches above the water on a spike grown from the tip of the stem. The aquatic weed can be easily confused with a common Indiana native plant, northern watermilfoil. For positive identification note that the leaves of Eurasian watermilfoil are limp when held out of water whereas the leaves of native plant stay rigid.

Eurasian watermilfoil can grow in a wide variety of habitats and conditions: ponds, lakes, reservoirs, and slow flowing rivers and streams. It will grow in shallow or deep water and does well in waters that have had some sort of disturbance like intense plant management, overabundance of nutrients, or extensive motorboat use. Eurasian watermilfoil reproduces by seed and vegetative means quickly contributing to issues with Indiana’s aquatic weed control.

Use treatments once plants are established but before flowering occurs. RestoreAccess Ultra is perfect for this weeds control in Indiana ponds and lakes. We do not recommend mechanical removal unless invasion is widespread as fragmentation of the plant can aid in its spread since dispersal through vegetative means is its main reproductive strategy. If that is the case we recommend using Lake Restoration’s LakeMaid .

Curlyleaf Pondweed

Curlyleaf pondweed is a submersed aquatic plant with oblong, wavy, blue-green leaves that attach to its stems in an alternate pattern. Leaves can be up to 3 inches long and a half inch wide. Curlyleaf pondweed produces small flowers that are arranged on dense terminal spikes that rise a few inches above the surface of the water. Curlyleaf can grow in a variety of different locales and sediment types. This plant can tolerate extreme conditions including low light and cold water temperatures and has even been found growing under 20 inches of snow covered ice.

This plant is native to Africa, Australia, and Eurasia and was accidentally introduced in the United States in the 1800’s. By the 1930’s it was well established in the midwest and is now in all but 2 of the lower 48 states.

Curlyleaf pondweed is usually introduced to new bodies of water through the transport of plant fragments on aquatic equipment like boats and trailers. Curlyleaf’s dense growth can reduce the opportunity for water recreational activities and can decrease values of properties on lakes with a heavy infestation of the weed. We recommend using RestoreAccess Ultra to control the invasion of this aquatic weed.

Blue-Green Algae

Blue-green algae are present in almost all freshwater bodies in the United States. There have been several taste fouling or toxin producing blue-green algae species found in Indiana water supply lakes.

Blue-green algae can spread naturally through connected waterways, but humans can also be responsible for its movement from one body of water to another through contaminated boats, trailers or bait buckets.

Fish and other aquatic organisms can be affected during blue-green algae blooms by fluctuations of dissolved oxygen and pH of the water. These can occasionally trigger fish kills.

For pond algae or lake algae control, we recommend the copper based algaecide Mizzen™ To slow the re-growth of algae, we recommend using pond dyes that will filter the sun’s rays and allow for less photosynthesis to occur. Pond control products such as SparKlear® and PhosControl® will reduce the nutrients available to the algae, also leading to a slowing of regrowth. All of these products are available packaged together in PondRestore® Ultra.

Brittle Naiad

Brittle Naiad (najas minor) grows in dense clusters with highly branched stems that fragment easily (hence the name brittle) for easy propagation adding to Indiana’s aquatic weed control problems. Young leaves are medium green and flexible while older leaves are dark green, stiff, and brittle. This plant can also reproduce through tiny seeds which grow along the stem. It is highly invasive and inhibits the growth of native plants as well as making fishing difficult, and impeding the progress of a boat in a pond or lake.

Brittle Naiad originates in Europe, Turkey, North Africa, India and Japan. It was introduced into the United States in the 1900’s and first found in Ohio in 1932. It often grows with other submersed aquatic plants such as southern naiad, pondweed, coontail, and watermilfoil. And its preferred habitats include shallow water along lake shores, sheltered lake inlets, ponds, and streams with slow currents.

To control the growth of Brittle naiad we recommend the use of RestoreAccess Ultra or a good dose of Hydrothol 191.