Sikkim Knotweed (Koenigia mollis [Syn: Polygonum molle])

An introduced shrub native to India and Nepal. Possibly escaped from cultivation and naturalized along roadsides in the montane region.

* Also considers as a native plant of Sri Lanka as well >> 

Persicaria nepalensis

Native small herb occurs in moist montane areas. Common and often occurs as a weed of plantations. Flowering all the year round. 

Pink Rod/Common Marsh Duckwheat (Persicaria glabra [Syn: Polygonum glabrum)

Common native large herb occurs in ditches, waste places, wet places and shallow water in the low country.

සුදු කිඹුල්වැන්න[Sudu Kimbulwenna]/Water smartweed (Persicaria pulchra [Syn: Persicaria attenuata/Polygonum tomentosum/Persicaria attenuata subsp. pulchra/Polygonum pulchrum)

Common native herb occurs along tank margins, ditches, paddy fields and such wet places in the lowlands. Particularly in the dry zone. 

Persicaria chinensis

Native woody herb or sub-shrub climbing and scrambling over other vegetation along roadsides and forest margins in wet montane areas. 

Coral vine/Mexican Creeper (Antigonon leptopus)

An introduced large herb climbing with long tendrils over walls, hedges and other vegetation. Native to the central America. Flowering throughout the year. Cultivated as an ornamental and also escaped and naturalized.

Pink-headed Knotweed (Persicaria capitata)

An indigenous creeping herb.  Flowering throughout the year and growing on the ground, rock surfaces and over walls in the montane areas.