Common Name: Swamp Smartweed
Scientific Name: Persicaria hydropiperoides
Order: Polygonales
Family: Polygonaceae
Wetland Plant Status: Obligatory
Ecology & Description Swamp smartweed reproduces using seeds, rhizomes, and underground roots. They typically grow to be 2-3 feet high. The stem is normally unbranched and can sometimes seem red-striped. The leaves on this stem are oblong, tapering on both ends, have smooth margins, and alternate of one another. This plant is a very slow grower. The leaves are normally up to 6 inches long and floating on the water. The root systems are very extensive. At each leaf a node forms; it is not uncommon to see roots coming from each node. Flowers on swamp smartweed are 4-5 mm long and 2-5 mm wide. They form oblong spikes that are clustered at the tip of the flowers stalk. They range in colors from greenish, pink, or white and bloom throughout spring and fall. This plant is classified at a forb/herb lacking the ability to produce secondary growth, meaning it does not have stems other than the main one and it does not grow wide. The fruit on the swamp smartweed is dark brown to black, three-sided, and smooth and shiny. It is known as the “nonedible pepper” and it is dry but it does not split open when it is ripe.
Habitat Swamp smartweed grows in bodies of fresh water in the United States.
Distribution Swamp smartweed is found all over the majority of the United States and is only threatened in Indiana and New York.
Native/Invasive Status Swamp smartweed is native to the United States.
Wildlife Uses Swamp smartweed does not cause bloating in livestock; therefore, it is safe for consumption. Swamp smartweed is most commonly used as food by ducks and is great in beaver ponds.
Management & Control Techniques There are currently no conservation or management practices in place because swamp smart- weed grows in water. Cultivation is done manually. Some chemical control options such as: 2:4d and Dicamba can be used if necessary.
References Cardina, J., C. Herms, T. Koch, and T. Webster. 2015 Swamp Smartweed. Ohio Perennial and Biennial Weed Guide, Ohio State University. Online.
This document was authored by Macy Register, Department of Agricultural Science, Louisiana Tech University, April 2015.