DuPage County, IL Invasive Plant Rules: Prohibited Species (2026)
Key Facts
- Governing section
- Sec. 8-129.9 (Prohibited Plants)
- Trees banned
- 26 species, e.g. buckthorn, Callery pear, Siberian elm
- Shrubs/herbaceous banned
- 7 species, e.g. purple loosestrife, knotweed
- Applies to
- Landscape plans under Sec. 8-129.2
- Plan preparer
- Registered Illinois landscape architect
- Violation fine
- $100-$1,000 per day, Sec. 8-117.4
Summary
DuPage County's landscape regulations bar developers from using certain weak-wooded or invasive species to satisfy required screening and parking-lot landscaping. Sec. 8-129.9 lists 26 prohibited trees, including buckthorn, Callery pear and Siberian elm, plus seven prohibited shrubs and herbaceous plants such as purple loosestrife and Japanese knotweed.
8-129.9: - PROHIBITED PLANTS. The following plants shall not be planted as a part of meeting the screening and parking lot landscaping requirements: 1.Trees:...Rhamnus frangula Buckthorn Weak wood, fruit, seed spread by birds, very invasive...Pyrus calleryana Callery pear, Bradford, Cleveland, Aristocrat, etc. Self-seeds, litter, weak wood and branch structure, short lived, very invasive...Ulmus pumila Siberian elm Weak wood, disease, insects, self-seeds, invasive Shrubs/Herbaceous Plants: Coronilla varia Crownvetch Invasive, intolerant of other plants Lonicera japonica Japanese honeysuckle Very invasive, crowds out native understory plants Lythrum salicaria Purple loosestrife Very invasive, crowds out native plants Fallopia japonica Japanese knotwood, false or Mexican bamboo Very invasive, crowds out native plants Rosa multiflora Multiflora rose Very invasive, thorns Phalaris arundinaceous Reed canary grass Very invasive, crowds out native plants Phytolacca americana Pokeweed, American pokeweed Very invasive, crowds out native plants, are poisonous to pets and other animals
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 14 Update 1).
Full Breakdown
Sec. ' The tree table flags species such as box-elder, silver maple, tree-of-heaven, buckthorn, Callery pear, black locust, American elm and Siberian elm for weak wood, aggressive self-seeding, disease susceptibility or invasive roots; the shrub and herbaceous list adds crownvetch, Japanese honeysuckle, purple loosestrife, multiflora rose, reed canary grass, pokeweed and Fallopia japonica, described in the code as 'Japanese knotwood, false or Mexican bamboo,' each remarked as very invasive and crowding out native plants. The prohibition applies to every project required to submit a landscape plan under Sec.
2, which covers subdivisions, zoning-relief applications, developments with a transition yard, parking lots of 10,000 square feet or larger, projects with existing trees three inches or more in diameter, and any project with outdoor trash containers or stormwater basins. Landscape plans for nonresidential development, three-lot-or-larger subdivisions, and two-family or multifamily projects must be stamped by a landscape architect registered in Illinois. Sec. 1 explains the purpose: preserving healthy native and existing vegetation, discouraging self-seeding and invasive spread, and using native plantings around stormwater basins to filter runoff and cut down on nuisance waterfowl. Any plant material that dies must be replaced under the maintenance duty in Sec. 5(13).
Violations & Fines
Landscape-plan compliance is enforced through the Building Code's general penalty, Sec. 8-117.4: violating any provision of the code is 'punishable by a fine of not less than one hundred dollars ($100.00) nor more than one thousand dollars ($1,000.00),' with each day of noncompliance treated as a separate offense. Before that, the Building Official issues a written notice of violation and gives the property fourteen days to revise the planting plan or request an administrative appeal.
Frequently Asked Questions
Which trees can't count toward my required screening?
Can I still plant Japanese knotweed elsewhere on my property?
Who has to follow this prohibited-plant list?
What happens if a banned species shows up on an approved plan?
Sources & Official References
Other rules in DuPage County
Compare DuPage County to another location·View the Illinois invasive plant rules overview
See something wrong?
Help us keep this page accurate. If you notice an error or outdated information, let us know.