Polygonaceae
Leathery knotweed
Polygonum achoreum
- Family
- Polygonaceae
- Genus
- Polygonum
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Common names
By language (3)
- English
- Leathery knotweed
- Finnish
- Lusikkatatar
- Swedish
- Pilgrimstrampört
Synonyms
- Polygonum erectum subsp. achoreum (S.F.Blake) Á.Löve & D.Löve
Flowers
- In flower
- July to September (from 31 flowering iNaturalist observations worldwide)
Characteristics
- Growth habit
- Forb/herb
- Lifespan
- Annual
- In the US and Canada
- Alaska: native, Canada: native, Lower 48 states: native
Photos
FlowerPhoto: Alison Northup, CC BY 4.0, from iNaturalist 
FlowerPhoto: Henrique Pacheco, CC BY 4.0, from iNaturalist 
FlowerPhoto: Matt Lavin, CC BY 4.0, from iNaturalist 
FlowerPhoto: Camille Boucher, CC0, from iNaturalist 
FruitPhoto: Ryan Hodnett, CC BY-SA 4.0, from iNaturalist 
Photo: Matt Lavin from Bozeman, Montana, USA, CC BY-SA 2.0, from Wikimedia Commons 
Photo: Matt Lavin from Bozeman, Montana, USA, CC BY-SA 2.0, from Wikimedia Commons 
Photo: Matt Lavin from Bozeman, Montana, USA, CC BY-SA 2.0, from Wikimedia Commons 
Photo: Matt Lavin from Bozeman, Montana, USA, CC BY-SA 2.0, from Wikimedia Commons 
Photo: Carter Ertel, CC BY 4.0, from iNaturalist 
Photo: Matt Lavin from Bozeman, Montana, USA, CC BY-SA 2.0, from Wikimedia Commons 
Photo: Quinten Wiegersma, CC BY 4.0, from iNaturalist
More in Polygonum
- Yard knotweedPolygonum avicularePolygonaceae
- Oval-leaf knotweedPolygonum arenastrumPolygonaceae
- Polygonum maritimumPolygonaceae
- Asiatic tearthumbPolygonum perfoliatumPolygonaceae
- Bellard's smartweedPolygonum patulumPolygonaceae
- European knotweedPolygonum arenariumPolygonaceae
- Narrowleaf knotweedPolygonum bellardiiPolygonaceae
- Polygonum cognatumPolygonaceae
- Horse-tail knotweedPolygonum equisetiformePolygonaceae
- KnotweedPolygonum oxyspermumPolygonaceae
- Douglas' knotweedPolygonum douglasiiPolygonaceae
- Erect knotweedPolygonum erectumPolygonaceae
Sources: classification, synonyms from World Flora Online Plant List (2026-06, CC0 1.0); common names, popularity from Wikidata (2026-10-26, CC0 1.0); common names, US characteristics from USDA PLANTS Database (2025-05-29, CC0 1.0). About our plant data.