Persicaria hydropiper - Water-pepper

Phylum: Magnoliophyta - Class: Equisetopsida - Order: Caryophyllales - Family: Polygonaceae

Water-pepper, Persicaria hydropiper

This unimposing weed of wet places is one of the early colonisers of ground following major disturbance, but it easily overlooked because its pallid flowers are sovery small.


The upright branching stems of Water-pepper are hairless and have alternate blunt-tipped lanceolate leaves whose margins are fringed with fine hairs. This annual weed grows to between 20 and 75cm.

Flowers of Water-pepper, Persicaria hydropiper

Drooping spikes of tiny flowers, pink when in bud but greenish white when open, branch from sheathed nodes; the terminal flower spike is usually longer than the others.

The flowers are typically just 4mm long with a corolla comprising four or sometimes five petal-like segments joined near their greenish bases. Each hermaphrodite flower has six stamens, three fused carpels and three styles; the flowers are self fertilising, and reproduction is via seeds..


Water-pepper is common and widespread throughout Britain and Ireland except for the far north of Scotland.

This plant has a very wide global distribution that includes most of mainland Europe, North Africa, temperate parts of Asia, Australia, New Zealand and North America.

Water-pepper, Persicaria hydropiper, closeuo of flower and buds


You will find plenty of Water-pepper in ditches and other marshy areas and in the margins of small streams and ponds, although it is also quite commonly seen in dry areas where the ground has been disturbed - farm gateways, refuse tips and even building sites, for example.

Blooming Times

In Britain and Ireland Water-pepper blooms from June through to the end of September.


Leaves of Water-pepper have a strong peppery taste and have been used in oriental spice mixtures and, in small quantities, in salads.

Medicinal properties have been claimed for extracts from Persicaria hydropiper, and its acidic juices can be used to dye wool yellow.


Persicaria, the generic name, relates the shape of leaves of this group of plants to those of a peach tree. The specific epithet hydropiper translates to water pepper.

This flower gets its common name Water-pepper (sometimes written as Water Pepper) from its preference for wet habitats and the peppery taste of the leaves.

Similar Species

Amphibious Bistort Persicaria amphibia produces upright flower spikes and often grows with its roots permanently under water.

Redshank Persicaria maculosa often grow with Water-pepper; there are usually distinctive dark blotches on its leaves and is stems generally have a red flush, especially above nodes or knots.

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