Douglas' Knotweed vs Red-knotgrass

Polygonum douglasii compared with Polygonum patulum

Taxonomic Classification

Rank	Douglas' Knotweed	Red-knotgrass
Kingdom same	Plantae (plantas)	Plantae (plantas)
Phylum same	Magnoliophyta (Flowering Plants)	Magnoliophyta (Flowering Plants)
Class same	Magnoliopsida (Dicots)	Magnoliopsida (Dicots)
Order same	Caryophyllales (Caryophyllales)	Caryophyllales (Caryophyllales)
Family same	Polygonaceae	Polygonaceae
Genus same	Polygonum	Polygonum
Species	Polygonum douglasii	Polygonum patulum

Evolutionary Relationship

Douglas' Knotweed and Red-knotgrass share a common ancestor at the Genus level: Polygonum.

Conservation Status

Douglas' Knotweed

NE — Not Evaluated

Red-knotgrass

NE — Not Evaluated

Physical Characteristics

Attribute	Douglas' Knotweed	Red-knotgrass
Diet	—	—
Average Lifespan	—	—
Average Length	—	—
Average Weight	—	—

Habitat & Geographic Range

Douglas' Knotweed

Habitat

Typically found in diverse terrestrial habitats from tropical forests to temperate regions.

Range

Distributed across Canada and United States.

Red-knotgrass

Habitat

Typically found in diverse terrestrial habitats from tropical forests to temperate regions.

Range

Widely distributed across Europe (16 countries), North America (Canada, United States), Oceania and the Pacific (Australia), and South America (Colombia).

Shared Countries

Both species can be found in 2 countries:

🇨🇦 Canada 🇺🇸 United States