Cal. Health and Safety Code - HSC § 14875. Section 14875.
“Weeds,” as used in this part, means vegetation growing upon streets, sidewalks, or private property in any county, including any fire protection district and may include any of the following:
(a)
Vegetation that bears seeds of a downy or wingy nature.
(b)
Vegetation that is not pruned or is otherwise neglected so as to attain such large growth as to become, when dry, a fire menace to adjacent improved property.
(c)
Vegetation that is otherwise noxious or dangerous.
(d)
Poison oak and poison ivy when the conditions of growth are such as to constitute a menace to the public health.
(e)
Dry grass, stubble, brush, litter, or other flammable material which endangers the public safety by creating a fire hazard in an urbanized portion of an unincorporated area which has been zoned for single and multiple residence purposes.