Practical ecological knowledge for the temperate reader.


"Habit: Annual, perennial herb, rhizomed or stoloned. Stem: prostrate to erect, ribbed or +- so or not, glabrous or hairy, generally with adventitious roots. Leaf: cauline, alternate, petioled or not; ocrea papery, rarely +- leaf-like, opaque, persistent or disintegrating, glabrous to variously hairy; blade lanceolate or ovate to hastate or sagittate, entire. Inflorescence: axillary, terminal, generally spike-like; flowers 1--14; peduncle present, pedicels present [or 0]. Flower: bisexual or functionally +- unisexual, base not stalk-like; perianth not or +- enlarging, bell-shaped (urn-shaped, rotate), glabrous, gland-dotted or not, green-white, white, pink, or red; perianth parts 4--5, fused 1/4--2/3, outer 2 > inner 2 or 3; stamens 5--8, filaments free, cylindric, thread-like, glabrous, outer fused to perianth tube or not, anthers elliptic to ovate, yellow, pink, or red; styles 2--3, erect to reflexed, free or fused, stigmas head-like. Fruit: included or exserted, brown or dark-brown to black, not winged, discoid, lens-shaped, or 3-angled. Seed: embryo curved."
Species In Genus: "+- 100 species: +- worldwide. Etymology: (Latin: persica, peach, aria, pertaining to; from resemblance of leaves of some species to those of peach)" [Jepson]

Comment: "There is a close relationship between Persicaria, Bistorta and Polygonum." [Personal Observation]

Local Species;

    1. Persicaria amphibia var emersa - water smartweed [E-flora][TSFTK]
    2. Persicaria hydropiper - Marshpepper smartweed [E-flora][PCBC]
    3. Persicaria hydropiperoides - Small water-pepper [E-flora][PCBC]
    4. Persicaria lapathifolia - Willow weed [E-flora][PCBC][TSFTK]
    5. Persicaria maculosa - lady's-thumb [E-flora][PCBC]
    6. Persicaria minor - Asian knotweed [E-flora]
    7. Persicaria punctata - Small dotted smartweed [E-flora][PCBC]
    8. Persicaria wallichii - Himalayan knotweed [E-flora][PCBC]

Persicaria amphibia


Introduction: Persicaria amphibia is a highly polymorphic aquatic species with two recognized but intergrading varieties in North America: var. emersa and var. stipulacea (Flora North America 2010). Both are widespread in the US and Canada, with a few exceptions in the northwest and southeast (USDA 2010). Plants which bloom in water, or are sometimes stranded on land during draw down periods, are recognized as var. stipulacea, while plants that bloom on moist soil are recognized as var. emersa (Flora North America 2010). Aside from habitat, characters that separate the two varieties include habit (erect or prostrate) and inflorescence shape. [IFBC-E-flora]1

General: Perennial herb from a rhizome or stolon; stems prostrate and freely rooting to ascending, several, simple, with erect tips and flowering branches up to 30-80 cm tall/long. [IFBC-E-flora]1

Leaves: Basal leaves lacking; stem leaves lanceolate to egg-shaped, usually floating, smooth above, hairy to smooth below, the blades 5-15 cm long, the stalks up to 1/2 as long as the blades; stipules smooth to hairy, cylindric, 1-2 cm long. [IFBC-E-flora]1

Flowers: Inflorescence of 1 or 2 terminal or subterminal, spikelike panicles, 1-8 cm long, 1-2 cm wide; perianths scarlet to rose, 4-5 mm long, 5-lobed. [IFBC-E-flora]1

Fruits: Achenes, lens-shaped, brown to black, smooth, shiny or sometimes dull, 2.5-3 mm long. [IFBC-E-flora]1

Notes: Two intergrading varieties occur in BC:

Habitat/Range: Wet shorelines, ditches and shallow water in the lowland, steppe and montane zones; var. emersum - infrequent in S BC, rare northward to NE BC, var. stipulaceum - common throughout BC; N to AK, YT and NT, E to NF and S to FL, TX and CA. [IFBC-E-flora]1

Status: Native [E-flora]


Like Polygonum persicaria, "Water smartweed (Polygonum amphibium L.) can also cause photosensitivity." [Majak SPPWC]


"(whole plant) Hyperoside, avicularin, quercetin, kaempferol, quercimeritrin, luteolin-7-glucoside.48" [CRNAH]


Aphid Host Plant: "Aphis fabae, nasturtii; Aulacorthum solani; Capitophorus hippophaes; Rhopalosiphum nymphaeae" [Blackman AWHPS]

Persicaria hydropiper - Marshpepper Smartweed

"P. hydropiper is not grown commercially but has found an exceptionally impressive range of uses in folk medicine and also as a culinary herb, and this has led to the adoption of a rich variety of apt local names,..." [Bajaj MAPS 4]


Polygonum hydropiper L. [E-flora]


Introduction: Marshpepper smartweed is an introduced Eurasian species that is found in the southwestern and south-central part of the province. [IFBC-E-flora]3

General: Annual (occasionally perennial) herb from fibrous root; stems ascending to erect, several, simple to branched, tending to root at the nodes, more or less finely pitted or gland-dotted, peppery-tasting, 20-100 cm tall. [IFBC-E-flora]3

Leaves: Basal leaves lacking; stem leaves alternate, lanceolate or elliptic-lanceolate, sparsely hairy to smooth, the blades 3-7 cm long, somewhat reduced upward, the stalks short; stipules oblique, up to 15 mm long, usually sparsely hairy and fringed with bristly hairs at the top. [IFBC-E-flora]3

Flowers: Inflorescence of axillary and terminal, spikelike, scarcely interrupted, drooping racemes, 2-7 cm long; perianths 2.5-4 mm long, glandular-dotted, greenish with white (pink) margins, usually 4-lobed about 2/3 the distance to the base; stamens usually six. [IFBC-E-flora]3

Fruits: Achenes, lens-shaped or 3-angled, brown, finely glandular-dotted, dull, 2.5-3 mm long. [IFBC-E-flora]3

Notes: Closely related to P. punctatum. [IFBC-E-flora]3

Habitat/Range: "The plant is indigenous to large parts of Europe, Asian Russia and Arctic regions." [PDR] "Moist ditches, shorelines and disturbed sites; common in SW, infrequent in SC BC; introduced from Eurasia." [IFBC-E-flora]3

Status: Exotic [E-flora]3

Hazards: "The consumption of larger quantities of the fresh kraut can lead to gastroenteritis. External use is not advisable because of the drugs irritant effect on the skin." [PDR] "The flower heads have little odour but all the aerial parts have a bitter acrid taste and contain vesicant compounds that blister the skin upon repeated handling (Clapham et al. 1952)." [Bajaj MAPS 4] "Plant is potentially allergenic (FAD)." [HMH Duke]

Activities: Hemostyptic [PDR]

"...pungent medicinal plants such as Polygonum hydropiper (Polygonaceae),... produce a-tocopherol (1876) and d-tocotrienol (1876a) (297). These tocopherols may play an important role as antioxidants for not only sesqui- and diterpene dialdehydes, but also for other higher unsaturated terpenoids and lipids found in liverworts (82)." [Asakawa CCB] "Allergenic (1; FAD; HH2); Analgesic (1; DEM; PHR); Antibacterial (f; WOI); Anticapillary Fragility (1; FAD); Antifertility (1; HH2); Anti-implantation (1; MPI); Antimutagenic (1; HH2); Antirheumatic (f; PHR); Antiseptic (f; EFS); Carminative (f; DEP; EFS); Contraceptive (f; WOI); Diaphoretic (f; EFS); Diuretic (f; EFS; FAD; HH2); Emmenagogue (f;PNC); Hemostat (1; PHR); Hypotensive (1; WOI); Insectifuge (f; WOI); Irritant (f; PH2); Larvicide (1; WOI); Litholytic (f; WOI); Myorelaxant (1; WOI); Piscicide (1; DEM; HH2; WOI); FNF); Rubefacient (f; EFS); Sedative (f; WOI); Stimulant (f; DEP; EFS; PNC); Tonic (f; DEP); Uterotonic (f; EFS); Vasoconstrictor (f; EFS); Vermifuge (f; DEP)." [HMH Duke]


"Flavonoids: including rhamnazin, rhamnazin bisulfate, persicarin (isorhamnetine sulfate) quercitrin, and hyperoside" [PDR] "In our earlier work, sulfated, methylated and glycosidal flavonoids were isolated from Polygonum hydropiper (Haraguchi et al., 1992, 1996a; Yagi et al., 1994), a medicinal herb used as a spice in Japanese cuisine. They were effective in inhibiting linoleic acid peroxidation and in preventing the generation of superoxide anion." [BCNS]

Flavonol Glycosides: 3-Glucoside-7-sulfate & Quercetin 3,5-dimethyl ether (caryatin) from leaves [Andersen FCBA]

"P-cumaroyl glycosides: hydropiperoside" [PDR]

"Sesquiterpenes: sesquiterpene aldehydes (pungent substances), polygoidal (tadeonal), and warburganal" [PDR]

Tannins [PDR]

Essential Oil: "The essential oil from foliage (ca. 0.43% dry wt.) contains monoterpenoids with a variety of skeletons, e.g. l,4-cineole, car-3-ene, alpha and Beta-pinenes, fenchone, borneol, camphor, linaloyl acetate etc., but is otherwise unexceptional (Yankov and Damyanova 1969)." [Bajaj MAPS 4]

"Foliage also contains anthocyanidins and anthocyanins..., flavonoids including guercetin and kaempferol, and glycosides such as isorhamnetin and rhamnazin... caffeic, gallic, sinapic and many other aromatic acids... and other aromatics...; [Beta]-sitosterol and a variety of high molecular-mass linear hydrocarbons and waxes..." [Bajaj MAPS 4]

"Of especial interest are isocoumarins that possess antiinflamatory activity (Furata et al. 1986) and an unidentified fraction ofextract from foliage that is a potent anti-fertility agent for rats (Garg and Mathur 1972)." [Bajaj MAPS 4]

"(whole plant) Persicarin, rhamnazin, isotadeonal, quercimeritrin, tadeonal." [CRNAH]


Selenium Accumulation: Root: 21.33, Leaf: 27.57 (mg/kg DW) [Yuan et al., 2012]

Aphid Host Plant: "[Anoecia cornicola]; Aphis middletonii, nasturtii, spiraecola; Aulacorthum solani; Capitophorus [elaeagni], hippophaes, hippophaes ssp. javanicus, mitegoni; [Cryptomyzus galeopsidis, ribis]; Kaltenbachiella nirecola; Macrosiphum euphorbiae; Myzus persicae; Pemphigus sp.; Prociphilus erigeronensis; Sitobion miscanthi Trichosiphonaphis polygoni, polygonifoliae, polygoniformosana" [Blackman AWHPS]

Alleleopathic: "Water extracts of weeds—little seed canary grass (Phalaris minor Retz.), water pepper (Polygonum hydropiper), and lambs quarters (Chenopodium album)— reduced uptake of P and Zn in wheat roots and shoots with little seed canary grass having the greatest effect (Chakraverty et al. 2005)." [Cheema Alleleopathy]

Persicaria hydropiperoides - Small water-pepper


Persicaria lapathifolia - Willow Weed


Persicaria maculosa - Lady's-thumb

Persicaria minor - Asian Knotweed

Introduction: Asian knotweed is an introduced species of wet, muddy shorelines in British Columbia that originates in Europe. It is found in southwestern BC (Fraser Valley) and south-central BC. [E-flora]6

General: Annual herb from a fibrous root; stems prostrate to ascending, several, simple or branched, 10-40 cm tall/long. [IFBC-E-flora]6

Leaves: Basal leaves lacking; stem leaves alternate, linear to narrowly elliptic, the blades 3-10 cm long, 5-8 mm wide, the stalks short; stipules long coarse-hairy, the hairs extending about 1 mm beyond the tips. [IFBC-E-flora]6

Flowers: Inflorescence of several flowers in spikelike racemes; perianths pink or purplish (rarely white), 1.5-3.5 mm long. [IFBC-E-flora]6

Fruits: Achenes, 3-angled or lens-shaped, 2-2.5 mm long, black, smooth and shiny. [IFBC-E-flora]6

Habitat/Range: Wet, muddy shorelines in the lowland and steppe zones; infrequent in SW BC (lower Fraser Valley), rare in SC BC (Tranquille); introduced from Europe. [IFBC-E-flora]6

Status: Exotic [E-flora]6

Aphid Host Plant: "Aphis nasturtii; Capitophorus hippophaes, mitegoni" [Blackman AWHPS]

Researching the relationship to Polygonum odoratum

  • Polygonum odoratum (Persicaria odorata (Lour.) Sojak.) - Vietnamese Mint/Coriander
    • Taxonomy: "Persicaria odorata (Lour.) Soják [This species should not be confused with Polygonatum odoratum (Mill.) Druce, angular Solomon's seal, a Eurasian herb of the lily family, that is sometimes cultivated as an ornamental.] Potter et al. (1993) state that the identity of the plant known as rau ram in North America is somewhat uncertain, and they imply that it may be the same species that has been identified as Polygonum minus Hud." [Small CH]
    • Location and Climate Range: "The plant is cultivated in Australia for a number of years. Literature searches reveal very little about the origin, but most probably introduced into Australia by immigrants from South-East Asia. Polygonum minus Huds is spread across South-East Asia, where the taxonomy is very similar to P. odoratum. Both varieties are very similar, except P. odoratum has a broader leaf. The chemotaxonomy of both varieties is very similar [52]." [Hunter EO]
    • Food Use: "The baby leaves have a pungent coriander flavor, while the mature leaves have a hot, pungent, peppery flavor that can dominate. Use as a fresh leaf condiment, at the end of cooking. Important in Asian cuisane, this herb is used in noodle soups (pho) from vegetables, seafood, or meat, and also in stir-fried meat and vegetable dishes." [mcvicar GH]
    • Medicinal Use: "Medicinally, it is drunk as an infusion to ease indigestion. To get rid of dandruff, the leaves are pounded to extract the kesum oil, which is then massaged into the scalp prior to washing." [mcvicar GH]
    • Economic and Potential Uses: "As a source of natural aliphatic aldehydes, as a flvouring material and for natural aldehydic notes in perfumery." [Hunter EO]
    • Part of the Plant Containing Oil: "Leaves and to a lessor extent, the stems. Yields of P. odoratum oil in North-East Victoria are higher than yields in Northern Malaysia, which is probably due to the milder climate in Victoria [53]." [Hunter EO]
    • Method of Extraction: Steam distillation [Hunter EO]
    • Chemical Constituents: "1-decanol (alcohol C10) 3-4.0%, 1-dodecanol (alcohol C12) 5- 12.0%, decanal (aldehyde C10) 20-25.0% and dodecanal (aldehyde C12) 45-50.0% [54]." [Hunter EO]
    • Cultivation: "Grow in ordinary soil in sun or part shade. Makes a good container plant where it can be kept in bounds. Take rooted cuttings to overwinter in colder climates." [NAH Orr]

Persicaria punctata - Small dotted smartweed


General: Annual herb from a rhizome; stems prostrate to erect, solitary from the rooted rhizome, few to numerous, 30-100 cm tall/long. [IFBC-E-flora]7

Leaves: Basal leaves lacking; stem leaves alternate, lanceolate, mostly smooth, 5-10 cm long, short-stalked; stipules sparsely hairy, 10-15 mm long, sometimes fringed with bristly hairs at the tops. [IFBC-E-flora]7

Flowers: Inflorescence of axillary and terminal, spikelike, interrupted racemes; perianths greenish with white margins, glandular-dotted, 5-lobed to about 1/2 the distance to the base; stamens usually 8. [IFBC-E-flora]7

Fruits: Achenes, 2- to 3-angled, deep brownish-black to black, smooth, shiny. [IFBC-E-flora]7

Notes: Closely related to P. hydropiper. [IFBC-E-flora]7

Habitat/Range: Swamps and wet meadows in the lowland and steppe zone; rare in SW (lower Fraser Valley) and SC BC; E to NB and NS and S to FL, TX, MX and CA; S. Asia. [IFBC-E-flora]7

Status: Native [E-flora]7

Persicaria wallichii - Himalayan knotweed


Persicaria wallichii is considered an emerging invasive species in the Vancouver region by the Greater Vancouver Invasive Plant Council (2009). An emerging invasive is defined by them as: currently found in isolated, sparse populations but are rapidly expanding their range within the region. [E-flora]8

"Polygonum polystachyum is a PERENNIAL growing to 1.8 m (6ft) by 1.5 m (5ft) at a fast rate. It is hardy to zone (UK) 6. It is in flower from Jul to September, and the seeds ripen from Sep to October. The flowers are hermaphrodite (have both male and female organs)Suitable for: light (sandy), medium (loamy) and heavy (clay) soils. Suitable pH: acid, neutral and basic (alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It prefers moist soil." [PFAF]2

General: Perennial herb from strongly creeping rhizomes; stems erect, numerous, branched, 1-2 m tall, reddish-brown. [IFBC-E-flora]8

Leaves: Basal leaves lacking; stem leaves alternate, lanceolate, the blades up to 20 cm long, densely soft- hairy, the base rounded to somehat heart-shaped, often with 2 small lobes, the stalks short; stipules sheathing, entire. [IFBC-E-flora]8

Flowers: Inflorescence a wide, diffuse panicle; perianth segments white, 3-5 mm long, not keeled on the back.

Fruits: Apparently sterile in our range. [IFBC-E-flora]8

Habitat/Range: Mesic fields and waste places in the lowland zone; rare in extreme SW BC and the Queen Charlotte Islands; introduced from SC Asia. [IFBC-E-flora]8

Status: Exotic [E-flora]8

Hazards: [Same as for Persicaria maculosa] [PFAF]2

Cultivation "Succeeds in an ordinary garden soil[1] but prefers a moisture retentive not too fertile soil in sun or part shade[200]. Repays generous treatment[1]. A vigorously spreading plant, it is only really suitable for large areas of ground[233]. Plants are easily mistaken for P. campanulatum[51]. Plants seem to be immune to the predations of rabbits[233]." [PFAF]2

Propagation: "Seed - sow spring in a cold frame. Germination is usually free and easy. When they are large enough to handle, prick the seedlings out into individual pots and plant them out in the summer if they have reached sufficient size. If not, overwinter them in a cold frame and plant them out the following spring after the last expected frosts. Division in spring or autumn. Very easy, larger divisions can be planted out direct into their permanent positions. We have found that it is better to pot up the smaller divisions and grow them on in light shade in a cold frame until they are well established before planting them out in late spring or early summer." [PFAF]2


Pungent Compounds

"Polygodial is the major component of the medicinal plants Polygonum hydropiper, P. minus, and P. punctatum var. punctatum (Polygonaceae). It is noteworthy that some ferns, such as Blechnum fluviatile collected in New Zealand and the Argentinean Thelypteris hispidula, elaborate the pungent component, polygodial (548), together with related drimanes (77, 761)." [Asakawa CCB]

"5,7-Dihydroxychromone, isolated from P. persicaria and P. lapathifolium, was found to exhibit antigermination activity.13,14" [Cutler BANPP]

Other Species


Page last modified on March 15, 2017, at 01:46 AM