Pronounced (approximate): per-sih-KAR-ee-uh hi-dro-PIE-per
Follow the slender, hanging flower spikes back toward the stem. Small leaves mixed into the flowering shoots help distinguish this wetland smartweed from its close relatives. The flowers combine green coverings with white or pink tips.
Water Pepper photographed by Where’s Wildlife. Tap the photo to explore the complete gallery.
Scientific family: Polygonaceae
Common family: Buckwheat
Genus: Persicaria
Growth: Annual herb
Bloom: July–September in Wisconsin
Height: Usually 8–32 inches (20–80 cm)
Habitat: Streambanks, pond margins, marsh edges, and wet disturbed ground
Other names: Marsh-pepper Smartweed · Marsh Waterpepper
Scientific synonym: Polygonum hydropiper
Season and size vary with growing conditions. Wisconsin field notes · Botanical description
Explore reported sightings and their locations.
The small leaves within the flowering portion are especially useful in this colony. Follow one stem continuously so neighboring plants do not confuse the comparison.
Look along streams and ponds, in marshy ground, and in moist or wet disturbed places. Wisconsin plants typically bloom from July through September. This annual may stand upright or branch outward as it grows.
A wider view helps place the dangling spikes within the colony. Close views are still needed to compare similar smartweeds.
Dotted Smartweed (Persicaria punctata) can also have drooping spikes and gland-dotted flower coverings. Gland dots alone do not separate these two species.
Botanical keys distinguish Water Pepper by flowering spikes commonly interrupted by small leaves and mature fruits with a dull surface. Dotted Smartweed has leafless spikes and shiny mature fruits. Compare the Go Botany key.
Photo identification: the leafy flowering shoots strongly support Water Pepper in this series. Exposed mature fruits are not shown, so the fruit-surface distinction was not verified from these photographs.
Look for the tubular sheath at each leaf attachment and the green flower coverings around the tiny pale flowers. Some flowers may also develop within the upper stem sheaths, contributing to the species’ leafy flowering appearance.
Flora of North America describes these features. Also compare Swamp Smartweed (Persicaria hydropiperoides), whose flower coverings generally lack the conspicuous gland dots of Water Pepper.
These views are useful for the arrangement of flowers and leaves. Fine gland details and individual flower-part counts require a sharper close examination.
Water Pepper is native to Eurasia and introduced in North America, including Wisconsin and Illinois. The red status label identifies its non-native origin here.
U.S. Army Corps of Engineers wetland guide · Flora of North America distribution
Observation maps show reported sightings, not the limits of the species’ range.
Study the small leaves within the flowering shoots, then practice distinguishing Water Pepper from other smartweeds in the wildflower quiz.
