T.E.R:R.A.I.N - Taranaki Educational Resource: Research, Analysis and Information Network

Pink Knotweed (Polygonum capitatum)

Kingdom: Plantae
(Unranked): Angiosperms
(Unranked): Eudicots
(Unranked): Core eudicots
Order: Caryophyllales
Family: Polygonaceae
Genus: Persicaria
Binomial name: Persicaria capitata
Synonyms: Polygonum capitatum
Common names: Pink-head knotweed, Pink Knotweed, Japanese Knotweed or Pink bubble persicaria.

Persicaria capitata is a native of Asia. It is a tailing, perennial, evergreen prostrate herb whose alternate ovate leaves are 1–6 cm long, 0.7–3 cm wide with a reddish midrib with fine coloured hairs, giving a distinctive red ‘V’ pattern, with pink to red bands or blotches and short scattered hairs. This plant has a strong urine scented odour.It develops ball-like & numerous pink flowers (Oct-Mar).

It is found growing on roadsides, dry banks & slopes, open areas preferring full sun. Its impact on environment is that it forms a dense carpet replacing most native vegetation. It spreads locally from trailing stems that root easily and also garden dumping.

Polygonum capitatum has been widely used in China in the treatment of various urologic disorders including urinary calculus and urinary tract.



Persicaria capitata growing in full sunlight conditions.

Persicaria capitata growing in part shaded area.


Young leaves of Persicaria capitata


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