San Ramon, CA Landscaping Rules: Weed Ordinances (2026)
Key Facts
- Fee
- Contra Costa County Ag Commissioner enforces noxious weed controls per FAC §5004
- Rule
- Yellow starthistle, French/Scotch broom, and thistles are common targets
- Rule
- Owners of infested properties may receive county control orders
- Authority
- San Ramon can treat infestations as public nuisance under GC §39561
- Rule
- Volunteer opportunities available through EBRPD and Save Mount Diablo
Summary
Noxious weeds designated by the Contra Costa County Agricultural Commissioner under California Food and Agricultural Code Section 5004 must be controlled on private property. Common San Ramon targets include yellow starthistle, Italian thistle, French and Scotch broom, and artichoke thistle. Enforcement is handled by the county with city abatement backstop.
5004. “Noxious weed” means any species of plant that is, or is liable to be, troublesome, aggressive, intrusive, detrimental, or destructive to agriculture, silviculture, or important native species, and difficult to control or eradicate, which the director, by regulation, designates to be a noxious weed. In determining whether or not a species shall be designated a noxious weed for the purposes of protecting silviculture or important native plant species, the director shall not make that designation if the designation will be detrimental to agriculture. (Amended by Stats. 1992, Ch. 556, Sec. 1. Effective January 1, 1993.)
Full Breakdown
California Food and Agricultural Code Section 5004 gives the California Department of Food and Agriculture and each county agricultural commissioner authority to designate and enforce noxious weed controls. In Contra Costa County, the Department of Agriculture-Weights and Measures maintains a local noxious weed list and conducts inspections and educational outreach. Common noxious weeds found in and around San Ramon include yellow starthistle (Centaurea solstitialis), Italian thistle, milk thistle, artichoke thistle, French broom (Genista monspessulana), Scotch broom (Cytisus scoparius), and perennial pepperweed. These species spread aggressively, displace native vegetation, increase fire hazard, and reduce habitat value.
Property owners are expected to prevent the spread of A-rated and B-rated noxious weeds. Where infestations threaten adjacent properties, open space, or agricultural lands, the County Agricultural Commissioner may issue a control order. Non-compliance can lead to county-directed abatement with costs recovered from the owner. At the local level, San Ramon can additionally treat noxious weed infestations as a public nuisance under Government Code Section 39561. Residents in hillside and open space-adjacent properties should coordinate with neighbors and groups like Save Mount Diablo for invasive plant removal. The East Bay Regional Park District runs volunteer restoration days in nearby Las Trampas and Bishop Ranch Regional Preserve.
Frequently Asked Questions
Am I required to remove invasive plants on my property?
Where can I get help identifying weeds?
Sources & Official References
Other rules in San Ramon
How San Ramon compares: Cities with the Strictest Weed and Property Maintenance Rules·California rules heatmap·Compare San Ramon to another location·View the California landscaping rules overview
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Weed Ordinances in Nearby Cities
How other cities in Contra Costa County handle weed ordinances.