Colo. Rev. Stat. § 35-5-109
When noxious weeds, insect pests, or plant diseases are found on a property not listed on the tax rolls of the county and the owner or lessee of the property refuses or fails to take the necessary action to control or eradicate such noxious weeds, insect pests, or plant diseases, after notice as prescribed in section 35-5-108, the county pest inspector shall treat the same as though listed on the tax rolls, and the expense thereof may be recovered by the county in an action therefor in any court of competent jurisdiction. The control or eradication of noxious weeds, insect pests, or plant diseases on county property may be contracted for by the inspector, with the approval of the board of county commissioners, at county expense.
C.R.S. § 35-5-109