Weld County, CO Invasive Plant Rules: Prohibited Species (2026)
Key Facts
- Banned plants
- cottonwood, Siberian elm, Chinese elm
- Also banned
- Tree of Heaven, noxious weeds
- Applies to
- I-25 Overlay District landscape plans
- Reviewing agency
- Department of Planning Services
- Preferred alternative
- native, regionally adapted species
Summary
Weld County Code § 23-5-520(A)(3) bars five plant types from any landscaping design inside the I-25 Overlay District: cotton-bearing cottonwood, Siberian elm, Chinese elm, Tree of Heaven, and any noxious weed. The list applies whenever a development plan needs county landscaping approval along the I-25 corridor.
3.The following plant materials shall not be included in the landscaping design:a.Cotton-bearing cottonwood (Populus).b.Siberian elm (Ulmus pumila).c.Chinese elm (Ulmus parvifolia).d.Tree of Heaven (Ailanthus altissima).e.NOXIOUS WEEDS.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Charter and County Code: Supplement 95).
Full Breakdown
Section 23-5-520 governs landscaping design for development inside Weld County's I-25 Overlay District that triggers a site plan review, use by special review, special review permit, or Division 17 zoning permit under § 23-5-500. 3 flatly excludes five plant materials from any approved landscaping design: cotton-bearing cottonwood (Populus), Siberian elm (Ulmus pumila), Chinese elm (Ulmus parvifolia), Tree of Heaven (Ailanthus altissima), and noxious weeds generally. 2 that landscape designers maximize native species and, where native material isn't appropriate, use regionally adapted, noninvasive plants instead, with Appendix 23-I offering a partial list of species native or adapted to Colorado's Front Range.
4(a) before construction, checking the plant list against these exclusions as part of approving the site's landscaping. The prohibition is a design-review standard tied to that permitting process, not a freestanding countywide ban reaching every private yard in unincorporated Weld County.
Violations & Fines
A landscape plan listing a banned species can be rejected by the Department of Planning Services before a building permit issues. If a prohibited plant is installed anyway, enforcement runs through Chapter 23, Article X: § 23-10-20 makes it a misdemeanor with a fine of up to $100 per day, and § 23-10-40 allows a civil penalty of $25 to $1,000 per violation, with a continuing penalty of up to $100 per day until the planting is removed or replaced.
Frequently Asked Questions
Can I plant a cottonwood tree on my I-25-corridor commercial lot?
Does the ban reach residential yards outside the overlay?
What must I plant instead of the banned species?
Sources & Official References
Other rules in Weld County
Compare Weld County to another location·View the Colorado invasive plant rules overview
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