Polygonum sp.
Knotweed, Knotweed
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Family: Polygonaceae · Type: Perennial · Variable; species dependent
Polygonum sp. (Knotweed) is a non-native California perennial in the Polygonaceae family.
How to tell it apart
vs Euphorbia: Polygonum has swollen stem joints with papery sheaths; Euphorbia has milky sap when broken.; vs Persicaria: Hold node sheaths to light—Polygonum's are translucent and split; Persicaria's are opaque and intact.; vs Eriogonum: Polygonum has papery sheaths at nodes; Eriogonum has flowers in cup-like involucres.; vs Acmispon: Polygonum has swollen stem nodes; Acmispon has compound leaves with 3-5 leaflets.; vs Atriplex: Polygonum has papery stem sheaths; Atriplex has mealy or scurfy coating on leaves.
Frequently asked questions
Is Polygonum sp. native to California?
No. Polygonum sp. is not native to California (recorded as variable; species dependent).
What plant family does Polygonum sp. belong to?
Polygonum sp. is in the Polygonaceae family, genus Polygonum.
Related species
Other California species in the same genus, family, or bioregion.
- Polygonum spergulariiforme — Spurry knotweed
- Polygonum argyrocoleon — Persian knotweed
- Polygonum austiniae — Mrs. austin's knotweed
- Polygonum aviculare — Knotweed
- Polygonum aviculare subsp. aviculare
- Polygonum aviculare subsp. buxiforme
- Pterostegia drymarioides — Fairy mist
- Pterostegia sp. — Woodland threadstem
- Rumex acetosella — Sheep sorrel
Sources: Jepson eFlora · CalPhotos
Last updated 2026-04-14
Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, Cal-IPC, and more.