Polygonum sp. "Kawagoeanum"

Polygonum sp. 'Kawagoeanum' is another name for the knotweed listed here as Persicaria sp. 'Kawagoeanum', since Persicaria was long included in Polygonum.¹³ Its species is unresolved, and according to the specialist literature Persicaria kawagoeana is ruled out because of the leaf hairiness; it is also traded as Polygonum sp. 'Pink' or Persicaria sp. 'Red'.¹²³ It probably originates from Asia and colonises wet sites such as stream banks, ditches and marshes.¹²

Under water the willow-like leaves, 8–12 cm long, turn orange-red to pink or deep red in good light; the plant branches into a bush and looks best as a group in the midground.²³ Plenty of light, CO₂ and a good nutrient supply are needed; unsightly long shoots are replaced by top cuttings.²³ In the trade it is often passed off as Persicaria sp. 'Sao Paulo', with which it is easily confused.¹²

1. Persicaria sp. 'Kawagoeanum' – Flowgrow aquatic plant database (accessed 5 October 2026)
2. Persicaria sp. 'Kawagoeanum' – Aquasabi (accessed 5 October 2026)
3. Kasselmann, C. (2019): Aquarienpflanzen. 4th edition (German). - Ulmer Verlag, Stuttgart: p. 504.