Polygonaceae
Shasta knotweed
Polygonum shastense
- Family
- Polygonaceae
- Genus
- Polygonum
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Common names
By language (1)
- English
- Shasta knotweed
Flowers
- In flower
- July to September (from 48 flowering iNaturalist observations worldwide)
Characteristics
- Growth habit
- Shrub, Subshrub
- Lifespan
- Perennial
- In the US and Canada
- Lower 48 states: native
Photos
FlowerPhoto: Ben Sims, CC0, from iNaturalist 
FlowerPhoto: Matt Berger, CC BY 4.0, from iNaturalist 
FlowerPhoto: Matt Berger, CC BY 4.0, from iNaturalist 
FlowerPhoto: Matt Berger, CC BY 4.0, from iNaturalist 
Photo: Dcrjsr, CC BY 3.0, from Wikimedia Commons 
Photo: Adam J. Searcy, CC BY 4.0, from iNaturalist 
Photo: Dcrjsr, CC BY 3.0, from Wikimedia Commons 
Photo: Quinn Campbell, CC0, from iNaturalist 
Photo: Dcrjsr, CC BY 3.0, from Wikimedia Commons 
Photo: Adam J. Searcy, CC BY 4.0, from iNaturalist 
Photo: Dcrjsr, CC BY 3.0, from Wikimedia Commons 
Photo: Barbara Banfield, 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.