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Is Japanese knotweed illegal in California?
Sources (2)
Also called: Reynoutria (Fallopia) japonica. Last checked against official sources: 2026-10-14.
Federal noxious weed list (7 CFR 360.200): Japanese knotweed is not listed.
What California's official list says
| List / legal category | Listed as | List note | What it means |
|---|---|---|---|
| Noxious weed (3 CCR § 4500) | Fallopia japonica (=Polygonum cuspidatum; Reynoutria j.) | Japanese knotweed | Legally regulated — restrictions apply |
Effective dates
- The official list entry does not state a separate effective date for this species. See the linked law for when the listing took effect.
Already have it in your yard?
Noxious-weed rules can require control or restrict moving the plant (including soil, seed and cuttings). Check the exact wording above and the linked law.
Native alternatives for California
- Buttonbush (Cephalanthus occidentalis)
- American elderberry (Sambucus canadensis)
- Red osier dogwood (Cornus sericea)
Each is recorded as native to California in the USDA NRCS PLANTS Database state distribution (retrieved 2026-10-14). Check size, sun and soil fit for your site with your local Extension office.
More native swaps with hardiness, light and size →
Japanese knotweed in other states
Alabama Colorado Connecticut Delaware Idaho Illinois Indiana Kentucky Maine Massachusetts Michigan Minnesota Montana Nebraska New Hampshire New York Ohio Oregon Pennsylvania Utah Vermont Virginia Washington West Virginia Wisconsin
See every plant on California's invasive & noxious plant lists, or check any plant.
Not legal advice. PlantLegit summarizes official lists and links the source. Laws change, local (county/city) rules may add restrictions, and the official text controls. "What it means" is our plain-English label; read the exact list wording. Confirm with the agency before buying, selling or removing plants. Full disclaimer.