Lake County, IL Invasive Plant Rules: Prohibited Species (2026)
Key Facts
- Applies to
- Unincorporated Lake County developments only
- Listed species
- Buckthorn, purple loosestrife, honeysuckle, garlic mustard, black locust
- Penalty
- Up to $1,000 per day
- Enforced by
- Planning, Building and Development Director
Summary
Lake County's Unified Development Ordinance requires developers to remove buckthorn, purple loosestrife, honeysuckle, garlic mustard, reed canary grass and other invasive species from protected natural resource areas in unincorporated developments.
Maintenance of natural resource protection areas shall consist of the removal of litter, junk, and debris. Maintenance shall also include the removal of dead or diseased vegetation and such species as Lonicera tatarica (honeysuckle), Rhamnus cathartica (common buckthorn), Phalaris arundinacea (reed canary grass), Lythrum salicaria (purple loosestrife), Alliaria officinalis (garlic mustard), Rhamnus frangula (smooth buckthorn), Robinia pseudoacacia (black locust)...
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: 2026 S-15: Supplement contains: Local legislation current through Ord. 26-0618, passed 6-9-2026 | State legislation current through ILCS Pamphlet 2025 #5).
Full Breakdown
Under the county's Unified Development Ordinance, any development subject to the site capacity and site plan review process in unincorporated Lake County must maintain its designated open space and natural resource protection areas by removing dead or diseased vegetation along with named invasive species: honeysuckle, common buckthorn, reed canary grass, purple loosestrife, garlic mustard, smooth buckthorn and black locust, plus any other species the Planning, Building and Development Director determines detrimental to the protected resource. The duty applies only to unincorporated county land under county zoning jurisdiction. Waukegan, Highland Park, Libertyville, Gurnee and the county's other incorporated municipalities enforce their own separate codes for land within their limits.
Violations & Fines
No chapter-specific penalty is listed for this maintenance duty, so it falls under the county's general penalty: a fine of up to $1,000 for each violation, with every day of noncompliance counted as a separate offense.
Frequently Asked Questions
Does Lake County ban planting invasive species?
Does this rule apply inside Waukegan or Highland Park?
Sources & Official References
Other rules in Lake County
Compare Lake County to another location·View the Illinois invasive plant rules overview
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