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Practical ecological knowledge for the temperate reader.

Fallopia - Knotweed

"Habit: Annual, perennial herb, vine or not. Stem: erect, trailing, or twining, glabrous or hairy, ribs 0. Leaf: cauline, alternate, petioled; ocrea persistent or not, cylindric, papery, opaque; blade broad-ovate to triangular, entire. Inflorescence: axillary, terminal, spike-, panicle-, or raceme-like; flowers 3--7; peduncle present or 0. Flower: bisexual or pistillate (1 kind per pl); perianth generally enlarging, bell-shaped, pale green or white to pink, glabrous, base stalk-like, parts 5, fused basally or +- completely, of 2 kinds, outer 3 generally winged, > inner 2; stamens 6--8, filaments free, wider basally, glabrous or hairy, anthers yellow to pink or red, ovate to elliptic; styles 3, spreading, fused basally or +- completely, stigmas head-like, fringed, or peltate. Fruit: included or exserted, 3-angled, brown to black. Seed: embryo straight."
"Species In Genus: 12 species: America, Europe, Asia, Africa. Etymology: (for Gabriele Fallopio, 1523--1562, Italian professor of anatomy, botany, and surgery, for whom Fallopian tubes also named)" [Jepson]

Local Species;

  1. Fallopia convolvulus - Black Bindweed [E-flora]
  2. Fallopia japonica - Japanese knotweed [E-flora][PCBC]
  3. Fallopia sachalinensis - Giant knotweed [E-flora][PCBC]
  4. Fallopia xbohemica - Bohemian knotweed [E-flora]
F. convolvulus; "Moist to mesic waste places and fields in the lowland, steppe and montane zones infrequent in S BC, rare northward; introduced from Eurasia." [IFBC-E-flora-4]

F. japonica; "Moist to mesic ditches and disturbed sites in the lowland zone; frequent in the lower Fraser Valley, rare in the Queen Charlotte Islands, Powell River and SC BC; introduced from Asia." [IFBC-E-flora-1]

F. sachalinensis; "Mesic fields, roadsides and waste places in the lowland zone; infrequent on Vancouver Island, the Gulf Islands and the Vancouver area, rare on the midcoast (Prince Rupert); introduced from Asia." [IFBC-E-flora-2]
(above) Fallopia sachalinensis [Species level ID has not been verified with certainty.]

Fallopia convolvulus - Black Bindweed

"Polygonum convolvulus is a ANNUAL growing to 1.2 m (4ft). It is in flower from Jul to October. The flowers are hermaphrodite (have both male and female organs) and are pollinated by Insects, self.The plant is self-fertile."
"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]

Fallopia japonica - Japanese knotweed

"Polygonum japonicum is a PERENNIAL growing to 3 m (9ft) by 5 m (16ft) at a fast rate."
"It is hardy to zone (UK) 5. It is in flower from Jul to October, and the seeds ripen from Aug to October. The flowers are dioecious (individual flowers are either male or female, but only one sex is to be found on any one plant so both male and female plants must be grown if seed is required)The plant is not self-fertile."
"It is noted for attracting wildlife."
"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-1]

Introduction: "Japanese knotweed is an introduced and invasive species in British Columbia that is native to eastern Asia (Japan, China and Korea). It was imported as an ornamental plant and is sometimes used as a fence. It is a herbaceous perennial that thrives in disturbed sites, spreads rapidly, and forms thickets that are difficult to eradicate. New plants can grow from small pieces of root." "Japanaes knotweed is similar in appearance to Bohemian knotweed (Fallopia x bohemica) and giant knotweed (Fallopia sachalinensis) (though usually smaller) and hybridizes with giant knotweed." "Japanese knotweed is considered one of the top ten invasive plant species in British Columbia and is targeted for eradication. "The invasive root system and strong growth can damage foundations, buildings, flood defences, roads, paving, retaining walls and architectural sites. (Wikipedia 2012)." [E-flora-1]

"Knotweed, in the Buckwheat family, is not liked in western nations because it grows around three feet a month, sends roots down some 10 feet, grows through concrete, damaging roads, dams, buildings and just about anything made by man. It’s a pain in the asphalt." [EatTheWeeds]

Fallopia sachalinensis - Giant Knotweed

"Polygonum sachalinense is a PERENNIAL growing to 3.6 m (11ft) by 3 m (9ft) at a fast rate."
"It is hardy to zone (UK) 5. It is in flower from Jul to October, and the seeds ripen from Aug to October. The flowers are dioecious (individual flowers are either male or female, but only one sex is to be found on any one plant so both male and female plants must be grown if seed is required)The plant is not self-fertile."
"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-3]

Fallopia xbohemica - Bohemian knotweed

Hazards

Edible Uses

F. japonicum; "The Japanese once used it as a vegetable. The raw shoots are very reminiscent of rhubarb, and even the roots are edible. The stems can be boiled or roasted for use as a cooked green, or served fresh as a salad green. Japanese knotweed shoots can also be used to make jam, jelly, pie filling, and wine. Phillips (1986) gives a recipe entitled Japanese knotweed crumble. Szczawinski and Turner (1978) give several recipes, but note that some species of knotweed could cause photosensitization (hypersensitivity to light) with resulting dermatitis." [Small CH]

Other Uses

Medicinal Uses

Activities (F. japonica)
  • Antiaggregant (1; LAF); [HMH Duke]
  • Antialzheimeran (1; COX; FNF); [HMH Duke]
  • Antiarthritic (1; COX; FNF); [HMH Duke]
  • Antibacterial (1; LAF); [HMH Duke]
  • Anticancer (1; COX; FNF); [HMH Duke]
  • Antihistaminic (1; LAF);[HMH Duke]
  • Antiinflammatory (1; COX; FNF); [HMH Duke]
  • Antioxidant (1; COX; LAF); [HMH Duke]
  • Antitussive (1; LAF); [HMH Duke]
  • Antiviral (1; LAF); [HMH Duke]
  • COX-2 Inhibitor (1; COX; FNF); [HMH Duke]
  • Diuretic (1; DAA; FNF); [HMH Duke]
  • Emmenagogue (1; DAA; FNF);[HMH Duke]
  • Gonadotropic (1; DAA); [HMH Duke]
  • Glutathionigenic (1; COX; FNF); [HMH Duke]
  • Hepatoprotective (1; LAF); [HMH Duke]
  • Hypotensive (1; LAF); [HMH Duke]
  • Hypotriglyceridemic (1; LAF); [HMH Duke]
  • Lipolytic (1; LAF); [HMH Duke]
  • PTK-Inhibitor (1; LAF); [HMH Duke]
  • Stomachic (f; DAA); [HMH Duke]
  • Vasodilator (1; LAF) [HMH Duke]
Select Indications (F. japonica)
  • Abscess (1; DAA; FNF); [HMH Duke]
  • Alzheimer’s (1; COX; FNF); [HMH Duke]
  • Amenorrhea (f; DAA; LAF); [HMH Duke]
  • Appendicitis (1; DAA; LAF); [HMH Duke]
  • Arthrosis (1; COX; FNF); [HMH Duke]
  • Boil (1; DAA; FNF); [HMH Duke]
  • Bruise (1; DAA; FNF); [HMH Duke]
  • Burn (f; DAA; LAF); [HMH Duke]
  • Cancer (1; COX; FNF);[HMH Duke]
  • Dysmenorrhea (1; DAA; FNF); [HMH Duke]
  • Edema (1; COX; DAA); [HMH Duke]
  • Fever (1; COX; DAA; FNF); [HMH Duke]
  • Hepatosis (1; DAA; LAF); [HMH Duke]
  • Lymphadenosis (1; COX; DAA; FNF);[HMH Duke]
  • Pain (1; COX; LAF);[HMH Duke]
  • Pleurisy (1; DAA; FNF); [HMH Duke]
  • Snakebite (1; DAA; FNF); [HMH Duke]
  • Water Retention (1; DAA; FNF). [HMH Duke]

Phytochemicals

"Emodin (20), the most abundant and active anthraquinone in Cassia nigricans, is a purgative resin that was previously isolated from the Japanese knotweed (Fallopia japonica syn. Polygonum cuspidatum) [81]. Compound 20 is being studied as a potential agent that could reduce the impact of type 2 diabetes. It is a potent selective inhibitor of the enzyme 11B-hydroxysteroid dehydrogenase type 1 [82].... It has also been demonstrated that 20 has anticancer effects on several human cancers, including human pancreatic cancer [83-85], and its presence in extracts may also have neuroprotective properties against glutamate toxicity [78]." [Kuete MPRA]

"The stilbene resveratrol has assumed considerable relevance in recent years as a constituent of grapes and wine, as well as other food products, with antioxidant, anti-inflammatory, inhibition of platelet aggregation, and protective activity against cancer and cardiovascular diseases.... Resveratrol is available as a dietary supplement, though it is not currently regarded as a therapeutic agent. Commercial material is isolated from grapeskins or Japanese knotweed (Polygonum cuspidatum, syn. Fallopia japonica; Polygonaceae). Resveratrol also has antifungal properties..." [MNP Dewick]

"According to Kawano et al., the perennial herbs Fallopia japonica and F. sachalinesis (Polygonaceae) have EFNs at the base of the leaf petiole that secrete nectar that attracts nine ant species, wasps, flies, and beetles. When leaves are damaged by herbivores (Coleoptera and Hemiptera), the plants release two contrasting types of volatile substances. Within the first two hours after damage, the leaves release insect deterrents, and two hours after damage they start releasing a chemical signal attracting parasitoids to herbivores, creating a complicated defensive strategy that presents a complex and unpredictable environment for herbivores (Kawano et al. 1999). Volatile compounds (e.g., monoterpenes and fatty acid derivatives) commonly occur both in leaves when damaged and in flowers..." [Oliveira EEAPI]

Fallopia japonica - Japanese Knotweed [DukePhyt]
  • (+)-CATECHIN Root -- 2.0 ppm
  • 2,5-DIMETHYL-7-HYDROXYCHROMONE Root -- 2.0
  • 2,5-DIMETHYL-7-HYDROXYCHROMONE-7-MONOACETATE Root -- 0.5
  • 2-METHOXY-6-ACETYL-7-METHYL-JUGLONE Root -- 3.0
  • 2-METHOXY-6-ACETYL-7-METHYL-JUGLONE-MONOACETATE Root -- 0.5
  • 7-HYDROXY-4-METHOXY-5-METHYLCOUMARIN Root -- 3.0
  • 7-HYDROXY-4-METHOXY-5-METHYLCOUMARIN-8-MONOACETATE Root -- 0.5
  • ANTHRAQUINONES Root
  • CHRYSOPHANOL Root
  • CITREOROSEIN Root
  • EMODIN Root 4000.0 - 6700.0
  • EMODIN-8-BETA-D-GLUCOSIDE Root
  • EMODIN-8-GLUCOSIDE Root
  • FALLACINOL Root
  • ISOQUERCITRIN Plant
  • PHYSCION-8-BETA-D-GLUCOSIDE Root
  • PHYSCION-8-GLUCOSIDE Root
  • PICEID Root
  • PLASTOQUINONE-B Leaf
  • PLASTOQUINONE-C Leaf
  • POLYDATIN Plant
  • POLYDATOSIDE Root
  • POLYGONIN Root
  • POLYSACCHARIDES Root
  • PROTOCATECHUIC-ACID Root -- 1.0
  • QUERCITRIN Plant
  • QUESTIN Root
  • QUESTINOL Root -- 1.0
  • RESVERATROL Root
  • RESVERATROL Stem 30.0 - 50.0
  • RESVERATROL-3-MONOGLUCOSIDE Root
  • REYNOUTRIIN Leaf -- 3000.0
  • REYNOUTRIN Leaf -- 3000.0
  • RUTIN Plant
  • STILBENES Root
  • TORACHRYSONE-8-O-D-GLUCOSE Root -- 10.0
  • TORACHRYSONE-8-O-D-GLUCOSE-9-PENTACETATE Root -- 3.5

Cultivation

"The introductions of Fallopia japonica (Japanese knotweed) into the UK during the first half of the 19th century proved to be extremely aggressive, and almost impossible to eradicate; it is now officially regarded as Britain's most pernicious weed (Maby, 1996)." [Wickens, EB]

F. japonicum; "A very easily grown plant, it succeeds in ordinary garden soil in sun or shade[1, 111], though it prefers a moist soil in partial shade[187]. Japanese knotweed is an extremely invasive plant capable of sending up new shoots at a considerable distance from the main clump and also of growing up through tarmac[200]. The sub-species cuspidatum is the form that is most likely to cause problems. It is considered to be a pest in many areas, where it is forming large clumps in the wild and out-competing native species. If grown in the garden it should be planted within a strong barrier to contain its roots. The sub-species compacta is only about 70cm tall and is far less invasive, but should still not be grown in small gardens[200]. A report on the Natural History Programme stated that Japanese knotweed is actually becoming a very valuable habitat for spiders, frogs, grass snakes and many other creatures. Its hollow stems allow a wide variety of insects and other small creatures to overwinter and find hiding places, thus a greater abundance of food is provided for insectivores such as frogs, who are themselves eaten by grass snakes. In areas of north Wales where Japanese knotweed has run rife, it is now the primary habitat for grass snakes[215]. Plants seem to be immune to the predations of rabbits[233]. Often cultivated as a dye and a medicinal plant[46, 61]. Very closely related to P. conspicuum[58]. Dioecious, male and female plants must be grown if seed is required[58]." [PFAF-1]

"Trials in Haida Gwaii, British Columbia, using sea water sprayed on the foliage, have demonstrated promising results, which may prove to be a viable option for eradication where concerns over herbicide application are too great.[9]" [Wiki-1]

Propagation

Use of Other Fallopia Species

References

Page last modified on 5:20 AM February 20, 2024