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Persicaria hydropiper

waterpepper

Polygonaceae

Temperate Europe, Asia, and North Africa

Attracts Pollinators

SunFull Sun – Part Shade

WaterHigh

Overview

Persicaria hydropiper is an annual of wet ground, growing 8-30 inches (20-75 cm) tall on slender, often reddish, jointed stems that branch from the base. The lanceolate leaves are 2-4 inches (5-10 cm) long, mid-green and sometimes dark-blotched, with a membranous sheath (ocrea) clasping each node, and they redden as the season ends. Crushed foliage and sap have a sharp, peppery taste that gives the plant its common name. From midsummer into autumn it bears slender, nodding flower spikes 1-3 inches (2.5-8 cm) long; the tiny flowers are greenish-white flushed pink and are dotted with glands. The species grows in ditches, pond and stream margins, damp meadows, and disturbed wet soil, tolerating seasonal flooding but not prolonged drought. It self-seeds freely and can spread quickly on bare wet ground, which makes it a persistent volunteer in moist gardens. As an annual it dies after seeding and returns only from seed. The peppery young leaves are used in small amounts as a culinary flavoring, including as the Japanese herb tade.

Native Range

Persicaria hydropiper is native to temperate Europe, Asia, and North Africa, where it grows along ditches, ponds, streams, and damp open ground. It is widely naturalized beyond this range, including across much of North America.

Suggested Uses

Grown at pond and stream margins, in bog gardens, and in damp wildlife plantings where its seeds feed waterfowl and small birds. The peppery leaves are used sparingly as a culinary herb. Its free self-seeding limits its use in tidy formal beds.

How to Identify

Identified by lanceolate leaves with a peppery, acrid taste when chewed and a membranous sheath (ocrea) wrapping each stem node. The slender flower spikes nod at the tip and carry gland-dotted greenish-white to pink flowers. Stems are jointed and often flushed red. The sharp peppery sap separates it from the milder-tasting smartweeds it resembles.

Appearance

Size & Dimensions

Height8" - 2'6"

Width/Spread6" - 1'

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~12 weeks

Summer Fall

Slender nodding flower spikes appear from July to October. The individual flowers are 2-3 mm, greenish-white tinged pink, and gland-dotted. Small dark nutlets follow and ripen before the plant dies back in autumn.

Detailed Descriptions

Flower Description

Greenish-white flushed pink

Foliage Description

Mid-green, sometimes dark-blotched, reddening in autumn

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

Requires 4-8 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range5.0 - 7.0(Neutral)

357912

Soil Types

loam silt clay

Drainagewet

Water & Climate

Water Needs

High

Care & Maintenance

Care Guide

Persicaria hydropiper grows in full sun to partial shade on consistently wet, fertile soil, including ditches, pond edges, and damp meadows. It tolerates standing water and seasonal flooding but fails on dry ground. A slightly acidic to neutral loam, silt, or clay suits it. As an annual it is grown from seed sown on moist ground in spring, and it self-sows readily once established. No feeding is needed on naturally fertile wet soils. Spent plants die back after setting seed in autumn.