Polygonum persicaria (redshank)
- Summary of Invasiveness
- Taxonomic Tree
- Notes on Taxonomy and Nomenclature
- Plant Type
- Distribution Table
- History of Introduction and Spread
- Risk of Introduction
- Habitat List
- Hosts/Species Affected
- Host Plants and Other Plants Affected
- Growth Stages
- Biology and Ecology
- Latitude/Altitude Ranges
- Air Temperature
- Rainfall Regime
- Soil Tolerances
- Notes on Natural Enemies
- Means of Movement and Dispersal
- Pathway Vectors
- Plant Trade
- Impact Summary
- Environmental Impact
- Impact: Biodiversity
- Risk and Impact Factors
- 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 persicaria L.
Preferred Common Name
Other Scientific Names
- Persicaria dolichopoda (Ochi) Sasaki
- Persicaria maculata (Raf.) S.F. Gray
- Persicaria maculosa S.F. Gray
- Persicaria mitis Delarbre
- Persicaria persicaria (L.) Small
- Persicaria ruderalis (Salisb.) C.F. Reed
- Persicaria vulgaris Webb & Moq.
- Polygonum dubium Stein
- Polygonum fusiforme Greene
- Polygonum minus auct. non Huds.
- Polygonum puritanorum Fern.
- Polygonum vulgaris Samp.
International Common Names
- English: lady's thumb; ladysthumb
- Spanish: persicaria manchada
- French: persicaire douce; pied rouge
- Portuguese: erva-pessegueira
Local Common Names
- Brazil: persicaria-de-pe-vermelho
- Germany: floh knöterich
- Italy: persicaria
- Japan: harutade
- Netherlands: duizendknoop, kleine; perzikkruid
- New Zealand: willow weed
- Sweden: piloert, aaker-
- USA: heart's-ease; heartweed; spotted ladysthumb
- POLMI (Polygonum minus)
- POLPE (Polygonum persicaria)
- PRAVU (Persicaria vulgaris)
Summary of InvasivenessTop of page P. persicaria can be very competitive with crop plants, particularly in moist areas, and has an ability to spread rapidly once introduced to an area. The economic impact of P. persicaria in agricultural production is sufficient for various governments to declare this weed as a noxious pest (Anon., 1996; Anon., 2003). The state of Minnesota in the USA has declared P. persicaria as a secondary noxious weed and several states have categorized it as invasive (USDA-NRCS, 2002).
Taxonomic TreeTop of page
- Domain: Eukaryota
- Kingdom: Plantae
- Phylum: Spermatophyta
- Subphylum: Angiospermae
- Class: Dicotyledonae
- Order: Polygonales
- Family: Polygonaceae
- Genus: Polygonum
- Species: Polygonum persicaria
Notes on Taxonomy and NomenclatureTop of page P. persicaria is a summer annual, herbaceous, broadleaved (dicot) weed and is a member of the Polygonaceae, or smartweed family, also sometimes called the buckwheat, knotweed, or dock family. There are numerous varieties described by various authorities (e.g. Ekman and Knutson, 1994; Royal Botanic Gardens Kew, 2003; USDA-ARS, 2003). Several of these, such as var. minus, var. ruderale and var. vulgare appear to correspond to species now classified as accepted synonyms of P. persicaria. The taxonomical status of other varieties listed, var. angustiflorum Beckh., var. lapathiolium (L.) Meisn., var. opacum (Sam.) A.J. Li and var. vernicosa Cham & Schltdl. may correspond to other species and require confirmation. A form with white flowers rather than the usual deep pink, forma albiflora Millsp. has been described. Also, there are several separate authorities listed for P. persicaria (Royal Botanic Gardens Kew, 2003). This all indicates widespread variation in the species. Many Polygonum species, including P. persicaria, are now placed by a number of authorities in the genus Persicaria, hence Stace (1991) uses the synonym Persicaria maculosa and Grierson and Long (1983) use Persicaria dolichopoda.
DescriptionTop of page P. persicaria grows erect to spreading to 0.2-1.2 m tall and generally sprawls with age. Leaf blades lanceolate to elliptic-lanceolate, 3-15 cm long, 0.5-3 cm wide, glabrous to sparsely strigose, usually puncticulate, especially beneath, acute to long-acuminate, cuneate at the base, subsessile or on petioles to 1 cm long; ocreae 5-15 mm long, fringed with bristles, glabrous to strigose. Racemes usually globose to cylindric, 0.5-2.5 cm long, 0.5-1 cm thick. The leaves of this species typically have a dark green splotch, which is often 'V'-shaped, in their centres. The stems are glabrous, branching at base, erect, herbaceous, typically reddish at nodes. P. persicaria has a distinctly fringed ocrea, distinguishing it from other Polygonum species (Uva et al., 1997). The fringes on the P. persicaria ocrea are short, less than half the length of the membraneous ocrea. Roots are typically a taproot with branches. Flowers light to deep pink; calyx 2.5-3 mm long, 5-lobed to near the middle; stamens 6, included; style branches 2 or 3. The flowers are present July-September in the northern hemisphere. Achenes (seeds) are black, shiny, two-sided, lenticular or some often trigonous, 2-2.5 mm long.
Plant TypeTop of page Annual
DistributionTop of page P. persicaria is thought to be native to Europe, but is quite common in many other temperate and sub-tropical countries around the world and at high elevation in the tropics. The eastern limits to its native range appear to be uncertain however. Although it is known as a European or Eurasian native, it is also stated as a native of China (Flora of China Editorial Committee, 2003).
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.
|Continent/Country/Region||Distribution||Last Reported||Origin||First Reported||Invasive||Reference||Notes|
|Afghanistan||Present||Invasive||Holm et al., 1991|
|Bangladesh||Present||Introduced||Holm et al., 1991|
|Bhutan||Present||Grierson and Long, 1983|
|China||Restricted distribution||Native||Freedman, 1998; Flora of China Editorial Committee, 2003|
|-Fujian||Present||Native||Flora of China Editorial Committee, 2003|
|-Guangdong||Present||Native||Flora of China Editorial Committee, 2003|
|-Guizhou||Present||Native||Flora of China Editorial Committee, 2003|
|-Sichuan||Present||Native||Flora of China Editorial Committee, 2003|
|-Zhejiang||Present||Native||Flora of China Editorial Committee, 2003|
|India||Present||Sefaur and Mukherjee, 2010|
|-West Bengal||Present||Sefaur and Mukherjee, 2010|
|Iran||Present||Holm et al., 1991|
|Iraq||Present||Holm et al., 1991|
|Japan||Present||Invasive||Holm et al., 1991|
|Nepal||Present||Holm et al., 1991|
|Pakistan||Present||Holm et al., 1991|
|Philippines||Present||Invasive||Holm et al., 1991|
|Turkey||Present||Native||Holm et al., 1991; Royal Botanic Garden Edinburgh, 2003|
|Egypt||Present||Holm et al., 1991|
|Kenya||Present||Introduced||Holm et al., 1991|
|Tunisia||Present||Holm et al., 1991|
|Uganda||Present||Introduced||Holm et al., 1991|
|Canada||Present||Introduced||Invasive||Holm et al., 1991; Anon., 1996|
|-Quebec||Present||Bélair et al., 2007|
|Mexico||Present||Introduced||Holm et al., 1991; New York Botanical Garden, 2003|
|-Alaska||Present||Introduced||Not invasive||USDA-NRCS, 2002|
|-Arizona||Present||Introduced||Not invasive||USDA-NRCS, 2002|
|-Colorado||Present||Introduced||Not invasive||USDA-NRCS, 2002|
|-Idaho||Present||Introduced||Not invasive||USDA-NRCS, 2002|
|-Michigan||Present||Introduced||Invasive||USDA-NRCS, 2002; Weed Science Society of America, 2003|
|-Montana||Present||Introduced||Not invasive||USDA-NRCS, 2002|
|-Nevada||Present||Introduced||Not invasive||USDA-NRCS, 2002|
|-New Hampshire||Present||Introduced||Invasive||USDA-NRCS, 2002|
|-New Jersey||Present||Introduced||Invasive||USDA-NRCS, 2002|
|-New Mexico||Present||Introduced||Not invasive||USDA-NRCS, 2002|
|-New York||Present||Introduced||Invasive||USDA-NRCS, 2002|
|-North Carolina||Present||Introduced||Invasive||USDA-NRCS, 2002|
|-North Dakota||Present||Introduced||Invasive||USDA-NRCS, 2002|
|-Rhode Island||Present||Introduced||Invasive||USDA-NRCS, 2002|
|-South Carolina||Present||Introduced||Invasive||USDA-NRCS, 2002|
|-South Dakota||Present||Introduced||Invasive||USDA-NRCS, 2002|
|-Utah||Present||Introduced||Not invasive||USDA-NRCS, 2002|
|-West Virginia||Present||Introduced||Invasive||USDA-NRCS, 2002|
|-Wyoming||Present||Introduced||Not invasive||USDA-NRCS, 2002|
|Argentina||Present||Introduced||Invasive||New York Botanical Garden, 2003|
|Bolivia||Present||Introduced||Missouri Botanical Garden, 2003|
|Brazil||Present||Present based on regional distribution.|
|-Parana||Present||Introduced||New York Botanical Garden, 2003|
|-Rio Grande do Sul||Present||Introduced||New York Botanical Garden, 2003|
|Chile||Present||Introduced||Invasive||Holm et al., 1991; Pedreros et al., 2002|
|Colombia||Present||Introduced||Holm et al., 1991|
|Ecuador||Present||Introduced||New York Botanical Garden, 2003|
|Albania||Present||Native||Royal Botanic Garden Edinburgh, 2003|
|Austria||Present||Native||Invasive||Royal Botanic Garden Edinburgh, 2003|
|Belarus||Present||Native||Royal Botanic Garden Edinburgh, 2003|
|Belgium||Present||Native||Invasive||Royal Botanic Garden Edinburgh, 2003|
|Bulgaria||Present||Native||Royal Botanic Garden Edinburgh, 2003|
|Croatia||Present||Kristek et al., 2004|
|Czech Republic||Present||Native||Invasive||Royal Botanic Garden Edinburgh, 2003; Weed Science Society of America, 2003|
|Denmark||Present||Native||Invasive||INRA, 2001; Royal Botanic Garden Edinburgh, 2003|
|Estonia||Present||Native||Royal Botanic Garden Edinburgh, 2003|
|Faroe Islands||Present||Native||Royal Botanic Garden Edinburgh, 2003|
|Finland||Present||Native||Royal Botanic Garden Edinburgh, 2003|
|France||Present||Native||Invasive||INRA, 2001; Royal Botanic Garden Edinburgh, 2003; Weed Science Society of America, 2003|
|-Corsica||Present||Native||Royal Botanic Garden Edinburgh, 2003|
|Germany||Present||Native||Invasive||INRA, 2001; Royal Botanic Garden Edinburgh, 2003|
|Greece||Present||Native||Royal Botanic Garden Edinburgh, 2003|
|Hungary||Present||Native||Invasive||Royal Botanic Garden Edinburgh, 2003|
|Iceland||Present||Native||Royal Botanic Garden Edinburgh, 2003|
|Ireland||Present||Native||Invasive||Simmonds, 1946; Royal Botanic Garden Edinburgh, 2003|
|Italy||Present||Native||Invasive||INRA, 2001; Royal Botanic Garden Edinburgh, 2003|
|Latvia||Present||Native||Royal Botanic Garden Edinburgh, 2003|
|Lithuania||Present||Native||Royal Botanic Garden Edinburgh, 2003|
|Moldova||Present||Native||Royal Botanic Garden Edinburgh, 2003|
|Netherlands||Present||Native||Royal Botanic Garden Edinburgh, 2003|
|Norway||Present||Native||Invasive||Royal Botanic Garden Edinburgh, 2003|
|Poland||Present||Native||Invasive||Royal Botanic Garden Edinburgh, 2003|
|Portugal||Present||Native||Invasive||INRA, 2001; Royal Botanic Garden Edinburgh, 2003|
|-Azores||Present||Native||Royal Botanic Garden Edinburgh, 2003|
|Romania||Present||Native||Royal Botanic Garden Edinburgh, 2003|
|Russian Federation||Present||Present based on regional distribution.|
|-Central Russia||Present||Native||Royal Botanic Garden Edinburgh, 2003|
|-Northern Russia||Present||Native||Royal Botanic Garden Edinburgh, 2003|
|-Southern Russia||Present||Native||Royal Botanic Garden Edinburgh, 2003|
|Serbia||Present||Markovic et al., 2008|
|Slovenia||Present||Eler and Batic, 2002|
|Spain||Present||Native||Invasive||INRA, 2001; Royal Botanic Garden Edinburgh, 2003|
|-Balearic Islands||Present||Native||Royal Botanic Garden Edinburgh, 2003|
|Sweden||Present||Native||Invasive||Royal Botanic Garden Edinburgh, 2003|
|Switzerland||Present||Native||Royal Botanic Garden Edinburgh, 2003|
|UK||Present||Native||Invasive||Simmonds, 1946; INRA, 2001; Royal Botanic Garden Edinburgh, 2003|
|Ukraine||Present||Native||Royal Botanic Garden Edinburgh, 2003|
|Yugoslavia (Serbia and Montenegro)||Present||Native||Royal Botanic Garden Edinburgh, 2003|
|Australia||Present||Introduced||Holm et al., 1991|
|-Queensland||Present||Introduced||Adkins and Peters, 2001|
|New Zealand||Present||Introduced||Invasive||Holm et al., 1991; Weed Science Society of America, 2003|
History of Introduction and SpreadTop of page Spread of P. persicaria from Europe to other parts of the world appears to have been prevalent in the 1800s. It is now particularly common in eastern areas of North America, while also present in every continent.
Risk of IntroductionTop of page Due to the risks of both accidental and intentional introduction, either as a seed contaminant, via biotic or abiotic spread or from the importation of seed for ornamental planting, further spread of P. persicaria is likely. As a result, P. persicaria has been declared a noxious weed in parts of Canada (Anon., 1996) and the USA (USDA-NRCS, 2002).
HabitatTop of page P. persicaria grows best in moist to wet areas of waste ground, meadows, river banks, roadsides, railroads, and disturbed sites, including croplands and gardens. It is most prevalent near springs, shores, stream banks and ditches, especially irrigation ditches, where water is fresh. Plants often grow in wet moist soils, but tolerate periods of dryness. This species does not tolerate highly acidic soils (California Department of Food and Agriculture, 2003).
Habitat ListTop of page
|Terrestrial – Managed||Cultivated / agricultural land||Present, no further details||Harmful (pest or invasive)|
|Managed forests, plantations and orchards||Present, no further details||Harmful (pest or invasive)|
|Managed grasslands (grazing systems)||Present, no further details||Harmful (pest or invasive)|
|Disturbed areas||Present, no further details||Harmful (pest or invasive)|
|Rail / roadsides||Present, no further details||Harmful (pest or invasive)|
|Urban / peri-urban areas||Present, no further details||Harmful (pest or invasive)|
|Terrestrial ‑ Natural / Semi-natural||Natural forests||Present, no further details||Harmful (pest or invasive)|
|Natural grasslands||Present, no further details||Harmful (pest or invasive)|
|Riverbanks||Present, no further details||Harmful (pest or invasive)|
|Wetlands||Present, no further details||Harmful (pest or invasive)|
|Coastal areas||Present, no further details||Harmful (pest or invasive)|
Hosts/Species AffectedTop of page P. persicaria can be a serious weed of cultivated agricultural and horticultural crops. Holm et al. (1997) note that it is a weed of 35 crops including many unspecified vegetable and orchard crops.
Host Plants and Other Plants AffectedTop of page
|Allium cepa (onion)||Liliaceae||Other|
|Beta vulgaris (beetroot)||Chenopodiaceae||Main|
|Brassica rapa subsp. oleifera (turnip rape)||Brassicaceae||Other|
|Daucus carota (carrot)||Apiaceae||Other|
|Glycine max (soyabean)||Fabaceae||Main|
|Helianthus annuus (sunflower)||Asteraceae||Other|
|Hordeum vulgare (barley)||Poaceae||Main|
|Medicago sativa (lucerne)||Fabaceae||Other|
|Nicotiana tabacum (tobacco)||Solanaceae||Other|
|Phaseolus vulgaris (common bean)||Fabaceae||Other|
|Pisum sativum (pea)||Fabaceae||Other|
|Solanum tuberosum (potato)||Solanaceae||Main|
|Triticum aestivum (wheat)||Poaceae||Main|
|Zea mays (maize)||Poaceae||Main|
Growth StagesTop of page Flowering stage, Fruiting stage, Seedling stage, Vegetative growing stage
Biology and EcologyTop of page Genetics
P. persicaria has been found to hybridize with pale smartweed (P. lapathifolium). Compared with P. persicaria, the hybrid plants have narrower flower spikes and flatter achenes (California Department of Food and Agriculture, 2003). Flora Europaea (Royal Botanic Gardens Edinburgh, 2003) lists a number of hybrids including P. persicaria though considering the array of varietal synonymity the exact status of these requires verification. However, it is certain that there is widespread variation in the morphology of this species.
Physiology and Phenology
Research has shown that P. persicaria has a great deal of plasticity in its traits (Sultan and Bazzaz, 1993). For example, in a resource-rich environment, this species reproduced much more vigorously, while in a low-light environment it doubled the amount of leaf tissue (Sultan, 1996). Plants of this terrestrial summer annual typically do not form close colonies, but grow as scattered individuals. Plants are killed in the autumn by the first hard frost. Foliage turns brown to reddish and does not persist through the cold season (California Department of Food and Agriculture, 2003).
Propagation is by seed. Seeds fall near the parent plant, but often remain on the parent plant until scattered by animals or other disturbance. Once the seeds fall to the soil surface, they may be dispersed with water, animals, in soil movement, or with machinery. They may also survive crop harvest and become contaminants of crop seed. A persistent soil seed bank usually accumulates. Seeds are dormant when shed and require a cold, moist period to break dormancy. Length of initial seed dormancy varies widely on individual plants and between populations. Seeds normally germinate in the springtime, and those that do not germinate the first season enter secondary dormancy (California Department of Food and Agriculture, 2003). Research has shown that most seeds of P. persicaria easily emerge from most soil textures and from soil depths up to 50 mm (James et al., 2002). Seed longevity in the field is poorly documented. Under very rare conditions, fragmented stems can also regenerate into new plants (California Department of Food and Agriculture, 2003).
Climatic requirements include reasonable soil moisture. As noted above, cold, moist conditions are required to break seed dormancy. Although this weed thrives under moist conditions for much of the season, it can tolerate moderate summer droughts. P. persicaria plants have been found to elevations of 1500 m in California, USA (California Department of Food and Agriculture, 2003) or 1800 m in China (Flora of China Editorial Committee, 2003).
Although these plants are considered somewhat toxic, the seeds are frequently consumed by animals. Though rarely having a serious impact on P. persicaria, at least one virus disease (Arabis mosaic nepovirus) can utilize P. persicaria as a host, where symptoms are mosaics, mottling, chlorotic ringspots and sometimes necrosis. Generally these symptoms disappear soon after infection, but plants may remain stunted. This virus can be transmitted by nematodes or through infected seed.
Latitude/Altitude RangesTop of page
|Latitude North (°N)||Latitude South (°S)||Altitude Lower (m)||Altitude Upper (m)|
Air TemperatureTop of page
|Parameter||Lower limit||Upper limit|
|Absolute minimum temperature (ºC)||-20|
|Mean annual temperature (ºC)||5||20|
|Mean maximum temperature of hottest month (ºC)||13||30|
|Mean minimum temperature of coldest month (ºC)||-10||4|
RainfallTop of page
|Parameter||Lower limit||Upper limit||Description|
|Dry season duration||0||7||number of consecutive months with <40 mm rainfall|
|Mean annual rainfall||500||2500||mm; lower/upper limits|
Rainfall RegimeTop of page Summer
Soil TolerancesTop of page
- seasonally waterlogged
Notes on Natural EnemiesTop of page P. persicaria is a host to at least one virus disease (Arabis mosaic nepovirus), though this rarely has a serious impact on the plant.
Means of Movement and DispersalTop of page Natural Dispersal (Non-Biotic)
P. persicaria is propagated almost entirely by seeds which are produced in large numbers. Dispersal over short distances (1-10 m) is generally by wind or animals. Dispersal over longer distances can occur with water, particularly floods (NASD, 2002).
Vector Transmission (Biotic)
Birds and other animals can consume and disseminate seeds.
In agricultural areas, both cultivation and harvesting machinery can carry seeds from field to field.
Crop seeds need to be cleaned well to ensure that this and other weed seeds are not disseminated via crop seeds and planted with future crops.
P. persicaria seeds are sold for wildflower gardens. These sales are made through seed catalogues and over the internet and there exists the possibility of further introduction as a minor ornamental species.
Pathway VectorsTop of page
Plant TradeTop of page
|Plant parts liable to carry the pest in trade/transport||Pest stages||Borne internally||Borne externally||Visibility of pest or symptoms|
|Fruits (inc. pods)||seeds|
|Growing medium accompanying plants||seeds|
|True seeds (inc. grain)||seeds|
|Plant parts not known to carry the pest in trade/transport|
|Stems (above ground)/Shoots/Trunks/Branches|
Impact SummaryTop of page
|Fisheries / aquaculture||None|
ImpactTop of page P. persicaria can be very competitive with crop plants, particularly in moist soils and as such can have significant economic impacts in the requirements for use of increased tillage and herbicides, though exact data on costs due to the presence of this species are not known. Holm et al. (1997) note that it is a weed of 35 crops in 50 countries, those outside Europe including Australia, Brazil, Canada, New Zealand and the USA, also noting allelopathic effects on flax potatoes.
Environmental ImpactTop of page P. persicaria competes with natural vegetation, particularly in moist areas along ditches, streams, rivers, and marshes.
Impact: BiodiversityTop of page P. persicaria can compete strongly with other herbaceous vegetation in moist areas and as such can replace the natural vegetation and threaten biodiversity.
Risk and Impact FactorsTop of page Invasiveness
- Invasive in its native range
- Proved invasive outside its native range
- Highly adaptable to different environments
- Has high reproductive potential
- Has propagules that can remain viable for more than one year
- Negatively impacts agriculture
- Reduced native biodiversity
- Competition - monopolizing resources
- Pest and disease transmission
- Highly likely to be transported internationally accidentally
- Highly likely to be transported internationally deliberately
UsesTop of page During times of famine in China, P. persicaria leaves and stems have been consumed by humans (Freedman, 1998). In numerous countries, this weed is used as a decorative planting in flower gardens.
Similarities to Other Species/ConditionsTop of page P. persicaria has many similarities to P. pensylvanicum, but P. persicaria generally has a darkly pigmented mark on the leaf blade that is usually lacking on P. pensylvanicum (Uva et al., 1997). P. lapathifolium (= P. scabrum) is also similar but with green flowers and glandular dots on the under surface of upper leaves. P. cepitosum is similar but has a more rose-colored perianth and the bracts of the inflorescence have cilia which typically are longer than the flowers.
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
Intensive agricultural cultivation that does not allow emerged P. persicaria plants to mature will manage populations over time. Perennial turf or forages with frequent mowing will also deplete this weed.
Tillage/cultivation is effective for control of P. persicaria seedlings. The same is true of hoeing in home gardens and similar areas that can be managed by hand. Repeated mowing which prevents seed production will reduce populations over time.
Numerous herbicides are highly effective in controlling P. persicaria. However, in France from 1980, there were reports of biotypes of this weed resistant to Group C1/5 (photosystem II inhibitors) herbicides found in maize and other cropland. Research has shown that these particular biotypes are also resistant to atrazine and they may be cross-resistant to other Group C1/5 herbicides (Weed Science Society of America, 2003). Similar resistance to triazines has since been confirmed in the Czech Republic, New Zealand and the United States.
Although P. persicaria plants are susceptible to Arabis mosaic virus, no research has been undertaken on the development of biological control agents, whether viral or fungal. No arthropods known to attack this species specifically have been identified.
In agricultural and horticultural crops, P. persicaria can be managed through a combination of cultural, mechanical and chemical measures.
ReferencesTop of page
Anon., 1996. Manitoba Regulation Noxious Weeds Regulation - MR 38-5/96. http://web2.gov.mb.ca/laws/regs/pdf/n110-035.96.pdf.
Anon., 2003. Quebec Statutes and Regulations. Noxious Weeds. Agricultural Abuses Act. http://www.canlii.org/qc/regu/crqc/20030530/r.q.a-2r.1/whole.html.
Bélair G; Dauphinais N; Benoit DL; Fournier Y, 2007. Reproduction of Pratylenchus penetrans on 24 common weeds in potato fields in Québec. Journal of Nematology, 39(4):321-326. http://palmm.fcla.edu/nematode/index.htm
Cranston R; Ralph D; Wikeem B, 2002. Field Guide to Noxious and Other Selected Weeds of British Columbia. Government of British Columbia. Ministry of Agriculture, Food and Fisheries. http://www.agf.gov.bc.ca/cropprot/weedguid/weedguid.htm.
Eler K; Batic F, 2002. Phytocenological and agronomic classification of weed vegetation from intensively used fields of Kranjsko and Sor?ko polje. (Fitocenolo?ka in agronomska opredelitev plevelne vegetacije na intenzivno rabljenih njivah Kranjskega in Sor?kega polja.) In: Novi izzivi v poljedelstvu 2002. Zbornik simpozija, Ljubljana, Slovenia 5-6 decembra 2002. Ljubljana, Slovenia: Slovensko Agronomsko Drustvo (SAD), 368-372.
Flora of China Editorial Committee, 2003. Flora of China Web. Cambridge, Massachusetts, USA: Harvard University Herbaria. http://flora.huh.harvard.edu/china/.
Freedman R, 1998. Famine Foods. Polygonaceae. USA: Purdue University. http://www.hort.purdue.edu/newcrop/faminefoods/ff_families/POLYGONACEAE.html.
Grierson AJC; Long DG, 1983. Flora of Bhutan, Volume 1, Part 1. Edinburgh, UK: Royal Botanic Garden.
Holm LG; Doll J; Holm E; Pancho JV; Herberger JP, 1997. World Weeds: Natural Histories and Distribution. New York, USA: John Wiley & Sons Inc.
Holm LG; Pancho JV; Herberger JP; Plucknett DC, 1991. A Geographical Atlas of World Weeds. Malabar, Florida: Krieger.
INRA, 2001. Weed Science and Agronomy. HYPPA. Dijon, France: INRA. http://www.inra.fr/hyppa/hyppa-a/lamam_ah.htm.
James TK; Rahman A; Webster T; Waller J, 2002. Emergence of weeds as affected by vertical seed distribution in arable soils. New Zealand Plant Protection Volume 55, 2002. Proceedings of a conference, Centra Hotel, Rotorua, New Zealand, 13-15 August 2002, 213-217; 10 ref.
Kristek A; Kristek S; Antunovic M, 2004. Influence of fertilization and herbicides application on soil microflora and elements of sugar beet yield. (Utjecaj gnojidbe i primjene herbicida na biogenost tla i elemente prinosa ?ecerne repe.) Agriculture Scientific and Professional Review, 10(1):35-42.
Missouri Botanical Garden, 2003. VAScular Tropicos database. St. Louis, USA: Missouri Botanical Garden. http://mobot.mobot.org/W3T/Search/vast.html.
NASD, 2002. Weed management after a flood - strategies for this year and next. Madison, Wisconsin, USA: University of Wisconsin Cooperative Extension.
New York Botanical Garden, 2003. Catalogue of Vascular Plant Species of Eastern Brazil. Polygonaceae. http://www.nybg.org/bsci/hcol/sebc/Polygonaceae.html.
Royal Botanic Garden Edinburgh, 2003. Flora Europaea, Database of European Plants (ESFEDS). Edinburgh, UK: Royal Botanic Garden. http://rbg-web2.rbge.org.uk/FE/fe.html.
Royal Botanic Gardens Kew, 2003. Electronic Plant Information Centre. Kew, Richmond, London, UK. http://epic.kew.org/index.htm.
Sefaur Rahaman; Mukherjee PK, 2010. Bio-efficacy of herbicides in wheat (Triticum aestivum L.) in different tillage systems under terai agro-ecological region of West Bengal. Environment and Ecology, 28(1):1-5.
Simmonds NW, 1946. Biological flora of the British Isles. Polygonum L. em. Gaertn. Journal of Ecology, 33:117-143.
Stace C, 1991. New Flora of the British Isles. Cambridge, UK: Cambridge University Press.
USDA-ARS, 2003. Germplasm Resources Information Network (GRIN). Online Database. Beltsville, Maryland, USA: National Germplasm Resources Laboratory. https://npgsweb.ars-grin.gov/gringlobal/taxon/taxonomysearch.aspx
USDA-NRCS, 2002. The PLANTS Database, Version 3.5. National Plant Data Center, Baton Rouge, USA. http://plants.usda.gov.
Uva RH; Neal JC; DiTomaso JM, 1997. Weeds of the Northeast. Ithaca, USA: Cornell University Press.
Weed Science Society of America, 2003. International Survey of Herbicide Resistant Weeds. HRAC/ NAHRAC/ WSSA. http://www.weedscience.org/in.asp.
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/