Boulder, CO Landscaping Rules: Weed Ordinances (2026)

Section 6-2-3(a) prohibits any owner, lessee, agent, occupant, or person in possession or control of a lot or tract of land, occupied or not, from permitting or maintaining a growth of state-listed noxious weeds taller than twelve inches, whether on the lot itself or along the adjacent sidewalk, street, or alley. Colorado Department of Agriculture List A noxious species must be eradicated entirely, with no twelve-inch grace height at all. Chapter definitions in Section 6-2-2 limit "weeds" to grass and herbaceous plants, expressly excluding flower or vegetable garden plants, small plots of wheat, barley, oats, or rye, and planned, maintained shrubs and woody plants; the separate "brush" definition covers unmaintained woody shrubs outside a planned landscape, regulated instead under Section 6-2-4.

Enforcement under Section 6-2-3(b) runs through the city manager rather than straight to municipal court: after notice and a hearing under the city's quasi-judicial hearing procedures in Chapter 1-3, the manager may impose a civil penalty of $100 for a first violation of the same provision, $250 for a second, and $500 for a third, with a hearing officer able to adjust the amount based on evidence presented. Subsection (c) makes clear this civil-penalty path is in addition to, not instead of, the city's general criminal penalty authority under Section 5-2-4.

Notice of a violation is valid if hand delivered, emailed, mailed, telephoned, or posted on the premises under Subsection (d). Chapter 6-2 exempts mountain parks, streams and watercourses, open space, and stream rights-of-way from the height rule so those areas can stay in a natural-appearing state.