Arapahoe County, CO Invasive Plant Rules: Prohibited Species (2026)

a, Selection and Installation of Plant Materials, which governs every landscape plan submitted for development on unincorporated county land. Item 1 of that subsection requires all installed plants to come from the County's approved plant list unless Planning staff approves an alternative through design review, and item 5 requires at least 75 percent of installed plants to be native or drought-tolerant species drawn from the plant list's low or very-low water-use categories. Item 6 layers the noxious-species ban on top of those selection rules: any plant listed as noxious by Arapahoe County Weed Control, or appearing on the Colorado Department of Agriculture's Noxious Weed lists, cannot be installed as part of a project's landscaping, full stop, there is no discretionary exception written into this item the way there is for substitute plant species under item 7.

The surrounding requirements reinforce the same water-wise, low-impact intent: plants must be grouped into hydrozones by water use, hydrozones cannot be mixed except between the low and very-low categories, and every plant must meet the American Standard for Nursery Stock. Because the noxious-species list is maintained by the Colorado Department of Agriculture and by the County's own Weed Control division rather than printed as a fixed list inside the Land Development Code itself, an applicant has to check both current lists when preparing a landscape plan rather than relying on a static roster in the code text.