Polygonaceae
Seaside knotweed
Polygonum glaucum
- Family
- Polygonaceae
- Genus
- Polygonum
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Common names
By language (2)
- Arabic
- بطباط أزرق
- English
- Seaside knotweed
Flowers
- In flower
- July to September (from 15 flowering iNaturalist observations worldwide)
Characteristics
- Growth habit
- Forb/herb, Subshrub
- Lifespan
- Annual, Perennial
- In the US and Canada
- Lower 48 states: native
Photos
FlowerPhoto: Dan Wilder, CC0, from iNaturalist 
FlowerPhoto: Matt Pelikan, CC BY 4.0, from iNaturalist 
Photo: Zihao Wang, CC BY 4.0, from iNaturalist 
Photo: W Rao, CC BY 4.0, from iNaturalist 
Photo: harrier, CC BY 4.0, from iNaturalist 
Photo: Matt Pelikan, CC BY 4.0, from iNaturalist 
Photo: harrier, CC BY 4.0, from iNaturalist 
Photo: harrier, CC BY 4.0, from iNaturalist 
Photo: Matt Pelikan, CC BY 4.0, from iNaturalist 
Photo: Chase Mathey, CC BY 4.0, from iNaturalist 
Photo: Luanne Johnson, CC BY 4.0, from iNaturalist 
Photo: Luanne Johnson, 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 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.