Water Pennywort, Hydrocotyle spp, is an emergent pond weed. Common names for this marshy plant include marsh pennywort, manyflower pennywort, dollarweed, and floating pennywort. Variations include hydrocotyle vulgaris, hydrocotyle umbellata, hydrocotyle ranunculoides,and hydrocotyle verticillata.

Hydrocotyle has rooted creeping stems. Stalks grow vertically from stems. At the top of the stalks are round green leaves with scalloped edges. Leaves are up to 2 inches in diameter. Pennywort produces round clusters of white flowers.

Pennywort plant spreads by seed and by rhyzome.

Dollarweed is found around the shorelines of ponds, lakes, streams and in marshy wetland areas. Vegetation can be found growing in shallow water. It can creep out into water and float at the surface. The floating mats of penny wort can break free from the rooted mass and float freely.

Pennywort is a fast growing pond weed. It can quickly take over shorelines. Floating pennywort can spread over 7 inches in one day- its biomass can double in 3 to 7 days!

Marsh pennywort is native to some areas of the United States. Hydrocoytle provides habitat for small fish, frogs, and other aquatic life. It also hosts many insects.

This emergent weed provides food for waterfowl. Due to the host of aquatic life, pennywort also provides food for fish.

While pennywort provides a number of benefits it also has negative impacts if left unmanaged. Dense floating mats can reduce oxygen in the water. It also outcompetes other beneficial vegetation.

Pennywort often restricts flow in waterways and drainage outlets. Overgrowth also reduces boating and fishing activities.

Some hydrocoytle species are considered invasive throughout the United States and in Europe.

Propeller provides good control of water pennywort. Propeller flumioxazin is dissolved with water in a tank sprayer and then applied directly to vegetation.

Harvester is a fast acting herbicide for pennywort control. Harvester diquat is mixed with water and Aquatistick surfactant in a tank sprayer and applied directly to weeds.

Glyphosate 5.4 is a liquid aquatic herbicide that will work on pennywort that have reached the surface. Spray glyphosate mixed with surfactant directly on weeds above the water surface to kill vegetation to the roots.

There are no effective natural treatment options for control of pennywort.