Cook County, IL Invasive Plant Rules: Prohibited Species (2026)
Key Facts
- Applies to
- Unincorporated Cook County only
- Triggers
- Building permits, PUDs, special/unique uses
- Parking lot threshold
- Over 20 spaces
- Enforcer
- Commissioner of Building and Zoning
- Replacement deadline
- 30 days after notice
Summary
Required landscape plans in unincorporated Cook County may not use invasive species like buckthorn, purple loosestrife, and garlic mustard.
Invasive plants may not be utilized. A list of invasive plants that may not be utilized, and alternatives that may be utilized, is set forth in the table below... Rhamnus cathartica Common buckthorn R ... Lythrum salicaria Purple loosestrife R ...
Full Breakdown
Cook County Code § 126-64(d) bars invasive plants from any landscape plan submitted with a building permit, planned unit development, special or unique use, or a parking lot over 20 spaces in unincorporated Cook County. The Building and Zoning Department maintains a table of banned species, including common and glossy buckthorn, Japanese, Amur, Morrow's and Tatarian honeysuckle, purple loosestrife, and garlic mustard, paired with approved native alternatives. Plant material must otherwise be selected from an approved native-plant list, and property owners must keep landscaping in good condition and replace dead plants within 30 days of notice from the Commissioner.
Violations & Fines
Using a listed invasive species on a required landscape plan, or failing to replace dead/noncompliant plant material within 30 days of the Commissioner's notice, is a violation of Chapter 126, enforced under Article 13 of Appendix A (fines, penalties, injunctive relief).
Frequently Asked Questions
Does this ban apply in Chicago or other Cook County towns?
What plants are banned?
Sources & Official References
Other rules in Cook County
Compare Cook County to another location·View the Illinois invasive plant rules overview
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