Parker, CO Invasive Plant Rules: Prohibited Species (2026)

Section 6.01.280(d) makes it unlawful and a nuisance to sell or import into the Town, or to plant or cause to be planted, any female cottonwood tree, Boxelder or Siberian Elm, or other undesirable plants designated by ordinance, declaring the planting of these species a menace to public health, safety and welfare. The same section's noxious-plant definition in Section 6.01.280(b) names leafy spurge, diffuse knapweed, Russian knapweed and spotted knapweed as noxious plants outright, alongside any alien plant that aggressively invades native communities, poisons livestock, carries pests or disease, or otherwise harms agricultural or natural ecosystems.

Neighborhood Services may inspect a property for noxious-plant infestation on request, on a neighbor's complaint, or after visual observation from a public place, and must give the landowner notice naming the plants and the best control method, biological, chemical, mechanical or cultural, before compliance is due within 10 days. If the landowner does not comply, the Town may control the plants itself and assess the cost plus a 15% fee as a lien against the property, and denying Neighborhood Services entry after a valid search warrant is itself a separate violation under Section 6.01.280(g).