Marshpepper Smartweed

Other Common Names: water pepper, marshpepper knotweed, marsh waterpepper, waterpepper smartweed

(Polygonum hydropiper, Pesicaria hyropiper)


Marshpepper smartweed has dark green sword shaped leaves and flower spikes that droop. The tiny flowers are spaced out and typically green to white.


Fleshy stems grow upward three inches to three and a quarter feet tall, sporadically branching. Stems can be green or red. Dark green leaves are sword shaped and alternate. They grow one to six and a quarter inches long and two-tenths to eight-tenths of an inch wide. Multiple flower spikes grow on each stem and sometimes branch. Flower spikes droop and contain many tiny flowers in clusters. Flowers are green to white and can have pink tips occasionally.


The main characteristic that sets apart marshpepper smartweed from the other native species is the drooping flower spikes and the fact that the flowers rarely turn pink.


Marshpepper smartweed grows in low marshy ground or in mud along ditches, streams, rivers, and pools. Ducks and small birds feast on smartweed seeds. Mammals don’t typically eat this type of smartweed because of its strong peppery taste. Swamp smartweed, also known as mild waterpepper, has a milder peppery taste and is consumed more by mammals.


Marshpepper smartweed can be found in nearly all 50 states of the United States.


seeds, roots