Polygonum hydropiper (marsh pepper)
- Taxonomic Tree
- Notes on Taxonomy and Nomenclature
- Distribution Table
- Hosts/Species Affected
- Biology and Ecology
- Natural enemies
- Notes on Natural Enemies
- Similarities to Other Species/Conditions
- Prevention and Control
- Distribution Maps
Don't need the entire report?
Generate a print friendly version containing only the sections you need.Generate report
PicturesTop of page
IdentityTop of page
Preferred Scientific Name
- Polygonum hydropiper L. (1753)
Preferred Common Name
- marsh pepper
Other Scientific Names
- Persciaria hydropiper (L.) Spach
- Persicaria hydropiper (L.) Opiz
International Common Names
- English: marshpepper smartweed; redshank; smartpepper; water pepper; water willow
- Spanish: Persicaria picante; pimenta-de-agua; pimienta de agua; resquemona
- French: curage; persicaire acre; poivre d'eau; renouee poivre d'eau
- Chinese: pinyin; shui-liao
- Portuguese: persicaria mordaz
Local Common Names
- Algeria: felfel el ma
- Bangladesh: bishkatali; pakurmal; panimarich
- Denmark: bidende pileurt
- Egypt: qeddab; qordaab; qordeyb
- Finland: katkeratatar
- Germany: Knoeterich; Pfefferknoeterich; Pfeffer-Knoterich; Wasserpfeffer; Wasserpfeffer-Knoterich
- Hungary: borsus keserufu
- India: bishkatal; packurmul
- Italy: erba pepe; idropepe; pepe b'acqua; poligono pepe-acquatica
- Japan: yanagitabe; yanagitade
- Mexico: chillo
- Netherlands: waterpeper
- Norway: vasspepar
- Paraguay: caatai
- Poland: rdest ostrogorzki
- Saudi Arabia: fulful el ma; zangabil et kilab
- Sweden: bitterblad; bitterpillort
- Yugoslavia (Serbia and Montenegro): dvornik papreni; dvornik tankoklasni
- POLHY (Polygonum hydropiper)
Taxonomic TreeTop of page
- Domain: Eukaryota
- Kingdom: Plantae
- Phylum: Spermatophyta
- Subphylum: Angiospermae
- Class: Dicotyledonae
- Order: Polygonales
- Family: Polygonaceae
- Genus: Polygonum
- Species: Polygonum hydropiper
Notes on Taxonomy and NomenclatureTop of page The genera Polygonum and Persicaria are commonly combined as Polygonum, and together contain about 300 species. The generic name means 'many angles or joints', either with reference to the often angled lower stem with its swollen nodes or the frequently triangular fruits. Hydropiper means water-pepper, a reference to its aquatic or semi-aquatic habitat and the sharply peppery taste of all parts of the shoots.
The 2n chromosome number of P. hydropiper is 20 (Holm et al., 1997).
DescriptionTop of page P. hydropiper is an annual herb which normally reproduces only by seed.
The plant has a taproot that may grow to over 1 m deep, although it is usually much shorter.
The main stem is often procumbent at the base, and may root from the lower nodes. It commonly branches at the lower nodes to produce several erect or ascending stems, 15-80 cm tall. The stems are smooth and hairless to very finely hairy, swollen at the nodes, green to red or light brown, and are surrounded above each node by cylindrical membranous ochreas which are 0.5-1 cm long with bristly tips. The stems normally branch towards their tips.
The single leaves have short stalks which taper into slender finely hairy glandular blades 4-10 cm long. Emerging leaves are rolled downwards at the edges. Modified stipules known as ochreae sheath the stem above the junction of stem and petiole. In P. hydropiper these are about 5 mm long with a fringe of hairs about the same length.
Inflorescences occur at the tips of all branches and in the upper leaf axils. Each is a slender (often nodding) spike of well-spaced green to pink flowers, 2-4 mm long, the outer parts of which are covered with dark glands.
Fertilized flowers develop into hard, usually triangular (also flattened), 2-3.5 mm long, dark dull brown to black fruits which remain enclosed in the dried flowers.
The seedlings exhibit epigeal germination. The hypocotyl is slender, green and about 1 cm long, and the cotyledons oval, green, and about the same length. The juvenile leaves are rolled downwards at the margins as they emerge, and are slender, green, and 1-2 cm long.
DistributionTop of page P. hydropiper is most commonly reported from the USA, China, India, Taiwan and Japan. It is more common in the Northern Hemisphere, but also occurs in Argentina, Australia, Brazil, Chile and New Zealand. Although very widespread throughout temperate and tropical regions, P. hydropiper appears to be absent from Africa. However, this may be a false assumption based on lack of referenced recordings from that continent.
It is present all across Europe, with the exception of the Balearic and Faeroe Islands, Iceland and Spitzbergen (Chater and Webb, 1993).
Distribution TableTop of page
The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.
HabitatTop of page P. hydropiper is a warm or wet season annual herb, occurring wherever there is moist soil or standing water. It grows on poorly drained agricultural land, along creek, river, canal and stream banks, in marshes and swamps, in poorly drained hollows, and in seasonally flooded areas.
The species grows well in most soils including silts, peats, loams and sands, and whilst tolerating a wide range of pH frequently grows better in more acid situations (Holm et al., 1997).
Hosts/Species AffectedTop of page P. hydropiper is also a common weed in other (especially irrigated) crops, vegetables, pastures and gardens, as well as wasteland and roadsides. It is especially common and pervasive where the soil is damp or waterlogged.
Biology and EcologyTop of page P. hydropiper is an annual herb which reproduces mainly by seed, although broken stems may root at the nodes and grow into new plants.
In temperate climatic zones, it germinates as the soil and water warm up in spring, flowers during the summer, and produces fruits from mid summer until killed by the frost in autumn or winter (Holm et al., 1997). Timson (1966) has shown it to be self-pollinating and phenotypically variable. Individual plants produce 385-3300 seeds, each weighing 1-2.5 mg (Datta and Banerjee 1973).
Dormancy characteristics and germination requirements vary between seed lots. In the USA, Justice (1941) showed that stratification of fresh seeds at 2-4°C for 18 weeks improved the otherwise low germination to over 90%, whilst in Japan, Nakamura (1970) demonstrated that removal of the seed coat, alternating temperatures and light all stimulated increased germination. Germination was stimulated by far-red and red light, but not by gibberellic acid. Seeds from tropically adapted plants may show different germination requirements.
The fruits float in water, and are distributed by irrigation, flood and drainage waters and by human activities including contamination of crop and pasture seed, in soil and plant trash and by boats and fishing gear equipment. They are also likely to be eaten by water birds and may be carried either externally or internally by water buffalo, pigs, aquatic birds and other wildlife to new water bodies (Holm et al., 1997).
Seed dormancy may be prolonged, but probably varies significantly between collections. Seeds have survived from 4 to 36 months underwater (Shull, 1914; Comes et al., 1978), 6 months in sand (3% germination) and loam (66% germination) (Timson, 1966), and up to 50 years in field soil (Darlington, 1951).
As with most other plants, the degree of stem branching increases as plant density declines, and stomata occur primarily on the undersides of the leaves (Timson, 1966). Some genotypes have purplish seedlings (used to garnish white fish in Japan), and the degree of anthocyanin pigmentation varies with light intensity, temperature (greatest at 5-10°C) and plant age, and increases as nitrogen levels fall (Miura and Iwata, 1979, 1981).
Natural enemiesTop of page
|Natural enemy||Type||Life stages||Specificity||References||Biological control in||Biological control on|
Notes on Natural EnemiesTop of page No significant natural enemies have been recorded for P. hydropiper.
ImpactTop of page P. hydropiper is a competitive weed in a great many crops, especially in irrigated crops, in rice, and in other crops grown on poorly drained soils (Holm et al., 1997). It grows well in poorly drained pastures, and, being very unpalatable, reduces the value of the grazing. The species is allelopathic to rice (Holm et al., 1997).
UsesTop of page The purplish seedlings of P. hydropiper are used as a relish with fish dishes in Japan, and the dried leaves as a condiment in South-East Asia (Holm et al., 1997). Macerated plants are used as a fish poison in India. It is also used for the treatment of haemorrhoids and as a diuretic. (Holm et al., 1997).
Extracts from P. hydropiper have significant biocidal properties, for example, against nematodes (Sukul, 1970).
Similarities to Other Species/ConditionsTop of page There are very many species within the Polygonum/Persicaria complex, many of which occur in wet soils and are generally similar in appearance. to P. hydropiper. The species require a good local flora for accurate separation and identification.
One of the closest in appearance in Europe, is P. mite Schrank (= Persicaria laxiflora (Weihe) Opiz) which differs in lacking the biting taste, and in having glossy achenes. Others mostly have denser inflorescences including P. persicaria (qv), P. lapathifolium and P. nepalense (qv). Hafliger and Wolf (1988) and Parker (1992) illustrate these and a number of other weedy species and show distinguishing features, including, for example, the ochreae.
Prevention and ControlTop of page
Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.Cultural Control
Plants should be hand-pulled or mechanically controlled before flowering. They must be either uprooted or buried, as simply breaking the stem will result in resprouting at the soil surface.
Little work has been conducted on the chemical control of P. hydropiper, although significant literature is available for Polygonum species of dryland sites.
In Korea, Park et al. (1995) showed that cyhalofop + bentazone and cyhalofop + pendimethalin gave good control of a dryland rice weed mixture which included this species, whilst Seong et al. (1991) obtained similarly good control with sequential applications of butachlor or benthiocarb [thiobencarb] followed by bentazone + quinclorac.
In New Zealand pastures, Sanders et al. (1994) obtained good kill of P. hydropiper with thifensulfuron.
No biological control has been attempted against P. hydropiper (Julien 1992), although the beetle Gastrophysa atrocyanea has been shown to damage this species in trials against Rumex japonicus (Xiaoshui, 1991).
ReferencesTop of page
Chater AO; Webb DA, 1993. 2. Polygonum L. In: Tutin TG, Burges NA, Chater AO, Edmondson JR, Heywood VH, Moore DM, Valentine DH, Walters SM, Webb DA, eds. Flora Europaea Volume 1 Psilotaceae to Platanaceae 2nd edition. Cambridge, UK: Cambridge University Press, 91-97.
Datta S; Bannerjee A, 1973. Weight and number of weed seeds. Proceedings of the 4th Asian-Pacific Weed Science Society Conference, 1:87-91.
Guo ShuiLiang; Huang Hua; Chao Ke; Zhu YiJun, 2005. On caloric values and ash contents of ten weed species in Jinhua suburb and its adaptive significances. Bulletin of Botanical Research, 25(4):460-464.
Hafliger TJ; Wolf M, 1988. Dicot Weeds. 1. Basle, Switzerland: CIBA-GEIGY Ltd.
Hnatiuk RJ, 1990. Census of Australian Vascular Plants. Australian Flora and Fauna Series Number 11. Canberra, Australia: Australian Government Publishing Service.
Holm LG; Doll J; Holm E; Pancho JV; Herberger JP, 1997. World Weeds: Natural Histories and Distribution. New York, USA: John Wiley & Sons Inc.
Justice O, 1941. A Study Of Dormancy in seeds of Polygonum. Memoirs of Cornell University Agricultural Experimental Station, 253.
MacKee HS, 1985. Les Plantes Introduites et Cultivees en Nouvelle-Caledonie. Volume hors series, Flore de la Nouvelle-Caledonie et Dependances. Paris, France: Museum Nationelle d'Histoire Naturelle.
Miura H; Iwata M, 1979. Effect of nitrogen, phosphorous and potassium on anthocyanin content of the seedlings of Polygonum hydropiper L. Journal of the Japanese Horticultural Society, 48: 91-98.
Nakamura S, 1970. Germination of Polygonum hydropiper L. seeds. Bulletin of the Faculty of Agriculture, Yamaguti University, 21:78-83.
Park SungJun; Cho NamKi; Kang YoungKil; Song ChangKhil; Cho YoungIl, 2005. Effects of split nitrogen application on the density of creeping bentgrass. Journal of the Korean Society of Grassland Science, 25(2):119-124.
Sanders P; Rahman A, 1994. Evaluation of thifensulfuron for control of some pasture weeds. Proceedings of the forty seventh New Zealand plant protection conference, Waitangi, New Zealand, 9-11 August 1994 [edited by Popay, A. J.] Rotorua, New Zealand; New Zealand Plant Protection Society, 62-67
Shull G, 1914. The longevity of submerged seeds. Plant World, 17:329-337.
Timson J, 1996. Polygonum hydropiper L. Journal of Ecology, 54:815-821.
USDA, 1970. Selected Weeds of the United States. Agriculture Handbook No. 366. Washington DC, USA: United States Department of Agriculture, 324-325.
Wang ZR, 1990. Farmland Weeds in China. Beijing, China: Agricultural Publishing House.
Xiang MM, 2002. Pathogenic fungi from the weeds in fields in Guangdong province. Journal of South China Agricultural University, 23(1): 41-44.
Zehzad B; Azimzadeh R, 1997. Recognition and biology of aquatic and semi-aquatic weeds in irrigation systems of paddy fields in Guilan province. Applied Entomology and Phytopathology, 64(1/2):11; Pe30-Pe39.
Distribution MapsTop of page
Unsupported Web Browser:
One or more of the features that are needed to show you the maps functionality are not available in the web browser that you are using.
Please consider upgrading your browser to the latest version or installing a new browser.
More information about modern web browsers can be found at http://browsehappy.com/