Persicaria lapathifolia

Pale Knotweed

Erect or branching annual or biennial herb, stems sometimes white cottony, often swollen at lower nodes. Sheath at base of leaf hairless or with cottony hairs.

Additional information

  • SynonymPolygonum lapathifolium
  • FamilyPolygonaceae
  • StoreyLower storey
  • Sizeto 1.6 m high
  • Plant groupingAquatic & Semi aquatic
  • LeavesLance-shaped leaves 6-12 cm x 8-45 mm with short bristles on margins and main veins, densely gland-dotted and densely white-downy below.
  • Flower colourDull pink
  • Flowering timepeaking September to May
  • FlowersTiny flowers in dense narrow cylindric spikes 2-7 cm long, often branched in a terminal drooping bunch.
  • Bird attractingLeaves, seeds
  • Butterfly attractingNo
  • Frog habitatYes
  • Growing conditionsSemi-aquatic along permanent watercourses and in winter-wet wetlands. Often in disturbed areas. Full sun, semi-shade.
  • Garden useUse in bog gardens and winter wet swampy areas where it can form dense stands.
  • Commercially availableNo information available
  • Conservation statusRestricted distribution within the Shire but locally common.
Photographer/s: 1, 4 Helen Moss ©; 2, 3 Chris Lindorff, NatureShare ©

Plant Communities

  • 35 Floodplain Wetland Complex (EVC 172)
  • 41 Swamp Paperbark Riparian Thicket (EVC 59)
  • 39 Sedge Wetland Complex (EVC 136)
  • 43 Buxton Gum Swampy Riparian Woodland (EVC 83)
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