Species

Persicaria hydropiper

Etymology

Persicaria: Medieval name referring to the likeness of the leaves to a peach tree

Common Name(s)

water pepper

Authority

Persicaria hydropiper (L.) Spach

Family

Polygonaceae

Brief Description

Erect annual herb up to ca 75cm tall, with reddish stems, willow-shaped leaves and long slender flower spikes with small white (greenish flowers).

Flora Category

Vascular - Exotic

NVS Species Code

POLHYD

The National Vegetation Survey (NVS) Databank is a physical archive and electronic databank containing records of over 94,000 vegetation survey plots - including data from over 19,000 permanent plots. NVS maintains a standard set of species code abbreviations that correspond to standard scientific plant names from the Ngä Tipu o Aotearoa - New Zealand Plants database.

Structural Class

Dicotyledonous Herbs other than Composites

Synonyms

Polygonum hydropiper

Distribution

Abundant in lowland regions of the North and South Islands.

Habitat

Occurs on the edge of river banks and marshy areas, also occurring as a submerged plant in clear moderate flowing streams. Not usually grazed by livestock, especially cattle.

Features

The leaves are bright green, without markings, they are narrrow and lance shaped with a wavy edge, and up to 12 cm long. There is a membranous sheath (ochrea) at the base of each leaf, that is fringed with short hairs. The inflorescence is slender and drooping, the small flowers occur on short stalks , they are pink or cream (rarely white to greenish white). The fruit is a dull, pitted, dark brown nut. The plant is burning (peppery) to taste

Similar Taxa

Distinguished from Persicaria decipiens when flowering by the yellow glands on the tepals of Persicaria hydropiper. The flower heads of P. decipiens are usually erect, and the leaves are dark green/red and often have dark blotches on them; it also lacks the peppery flavour of P. hydropiper

Flowering

November-June

Flower Colours

Cream,Green

Fruiting

Autumn

Year Naturalised

1906

Origin

Temperate Eurasia, North Africa

Reason for Introduction

Unknown, possibly a seed contaminant

Control Techniques

Not controlled in New Zealand.

Life Cycle and Dispersal

Spreads by seed dispersed by water or waterfowl.

Attribution

Factsheet prepared by Paul Champion and Deborah Hofstra (NIWA).

References and further reading

Johnson PN, Brooke PA (1989).  Wetland plants in New Zealand.   DSIR Field Guide, DSIR Publishing, Wellington. 319pp.

Popay et al (2010).  An illustrated guide to common weeds of New Zealand, third edition.  NZ Plant Protection Society Inc, 416pp.

Coffey BT, Clayton JS (1988).  New Zealand water plants:  a guide to plants found in New Zealand freshwaters.  Ruakura Agricultural Cente. 65pp.

This page last updated on 7 Feb 2017