Illinois law requires every landowner and occupant to control and eradicate noxious weeds on their property using methods approved by the Illinois Department of Agriculture. If you don’t, the county can enter your land without your consent, do the work itself, bill you for the full cost, and attach a lien to the property if you don’t pay within six months. Noxious weeds in Illinois are governed primarily by the Illinois Noxious Weed Law (505 ILCS 100), with a separate statute — the Exotic Weed Act — covering a different and longer list of regulated plants.
Which Plants Are Designated Noxious Weeds
You don’t get to decide what counts. The Department of Agriculture publishes the current list in the Illinois Administrative Code at Section 220.60, and it contains eight entries:1Illinois General Assembly. Illinois Administrative Code Title 8, Part 220 – Illinois Noxious Weed Law – Section: 220.60 Noxious Weeds
- Marijuana (Cannabis sativa L.)
- Giant ragweed (Ambrosia trifida L.) — only within city, village, or incorporated town limits
- Common ragweed (Ambrosia artemisiifolia L.) — only within city, village, or incorporated town limits
- Canada thistle (Cirsium arvense)
- Perennial sowthistle (Sonchus arvensis)
- Musk thistle (Carduus nutans)
- Johnsongrass and related perennial sorghum crosses (Sorghum halepense, sorghum almum, and other rhizome-producing hybrids)
- Kudzu (Pueraria lobata)
The ragweed rule catches people off guard. Both ragweeds are noxious weeds only inside municipal boundaries. A rural landowner with ragweed across five acres has no obligation under this law to remove it; the same plant inside city limits triggers enforcement. Canada thistle, musk thistle, johnsongrass, and kudzu apply statewide.
What You’re Required to Do
The statute places the obligation on every person who owns or controls land in Illinois, and it names two distinct duties: control the spread, and eradicate the weeds, using methods and timelines approved by the Director of the Department of Agriculture.2Illinois General Assembly. Illinois Code 505 ILCS 100 – Illinois Noxious Weed Law Slowing a weed’s spread is not enough if approved methods to eliminate it exist.
The duty applies to both rural and urban property. County weed control superintendents survey infested land annually and report their findings to the Director and the county control authority.3Illinois General Assembly. Illinois Code 505 ILCS 100/15 Walking your property at least once a growing season and checking for the listed species is the practical minimum, because the alternative is finding out about a problem through a county notice.
Cost arrangements vary. A new infestation may be managed by the landowner alone, by the county alone, billed to the landowner after the county acts, or shared between the two.4Illinois Extension. Illinois Regulations Regarding Invasive Plant Species – Section: Illinois Noxious Weed Law Contacting your county’s control authority early tends to be far cheaper than waiting to be billed for unilateral action.
Herbicide Rules
Chemical control is common, and licensing rules determine what you can apply. General-use herbicides on your own property require no license. Applying restricted-use pesticides on your own land to produce an agricultural commodity requires a private applicator license from the Illinois Department of Agriculture.5Illinois Department of Agriculture. Certification and Licensing
Anyone applying pesticides in the course of employment — a lawn service, a hired farm worker — must hold a commercial applicator license regardless of whether the product is restricted-use or general-use.5Illinois Department of Agriculture. Certification and Licensing Hiring an unlicensed contractor creates liability for both of you.
What Happens If You Don’t Comply
Enforcement starts with notice. Counties publish general public notices about the obligation on a schedule tied to the growing season, but those are announcements and do not target any specific parcel. What matters to you is the individual written notice. When the county weed control superintendent identifies a problem on a specific property, the owner, occupant, or agent gets a written notice that names the weeds, specifies the required control method, and sets a deadline for the work.6Illinois General Assembly. Illinois Administrative Code Title 8, Part 220 – Illinois Noxious Weed Law – Section: 220.150
Ignore the individual notice, and the control authority may enter the land and do the work. The statute explicitly authorizes personnel to enter property under their jurisdiction to perform their duties without the owner’s consent and without exposure to trespass claims, so long as they exercise reasonable care.2Illinois General Assembly. Illinois Code 505 ILCS 100 – Illinois Noxious Weed Law
The full cost of the county’s work is charged to the landowner. If you don’t pay within six months, the unpaid amount becomes a lien against your property, and the statute preserves the county’s right to pursue other collection methods on top of the lien.2Illinois General Assembly. Illinois Code 505 ILCS 100 – Illinois Noxious Weed Law Collected amounts flow into the county’s Noxious Weed Control Fund or general fund.3Illinois General Assembly. Illinois Code 505 ILCS 100/15
Fines
Violating the Noxious Weed Law is a petty offense. The fine is up to $100 for a first offense and up to $200 for each subsequent offense.7Illinois General Assembly. Illinois Administrative Code Title 8, Part 220 – Illinois Noxious Weed Law Those numbers understate the real exposure. The financial hit comes from the cost-recovery bill for county-performed work, which for large parcels with heavy infestation can run several hundred dollars per acre.
Contesting a Bill
If the county bills you and you disagree with the amount, you have five days. A written protest must be filed with the Director of the Department of Agriculture within five days of notification of the charge. The Director holds a hearing and may adjust or affirm the amount.2Illinois General Assembly. Illinois Code 505 ILCS 100 – Illinois Noxious Weed Law
If you’re still dissatisfied, judicial review is available under the Administrative Review Law. Filing for judicial review automatically stays the Director’s order, though the court may require you to post a bond.2Illinois General Assembly. Illinois Code 505 ILCS 100 – Illinois Noxious Weed Law The five-day protest deadline is easy to miss, and missing it likely forecloses your administrative challenge.
The Exotic Weed Act Is a Separate Law
Many landowners assume the noxious weed list is the whole picture. It isn’t. Illinois maintains a separate statute — the Exotic Weed Act (525 ILCS 10) — administered by the Department of Natural Resources rather than the Department of Agriculture. Under this law it is illegal to buy, sell, distribute, or plant the seeds or plant parts of designated exotic weeds without a DNR permit.8Illinois DNR. Illinois Designated Exotic Weeds
The exotic weed list is much longer than the noxious weed list and includes species still sold at nurseries in other states: Japanese honeysuckle, multiflora rose, purple loosestrife, several buckthorn species (common, glossy, saw-toothed, dahurian, Japanese, and Chinese), kudzu, exotic bush honeysuckles, exotic olives (including autumn olive and Russian olive), salt cedar, poison hemlock, giant hogweed, Oriental bittersweet, lesser celandine, teasel, and Japanese, giant, and Bohemian knotweed.8Illinois DNR. Illinois Designated Exotic Weeds
Violation is a Class B misdemeanor, which can carry up to six months in jail and fines up to $1,500, and each day of a continuing violation counts as a separate offense. Exotic weeds offered for sale without a permit are subject to confiscation and destruction by DNR agents.9Justia Law. Illinois Code 525 ILCS 10 – Illinois Exotic Weed Act Check plants against this list before buying honeysuckle, buckthorn, or olive varieties online or at garden centers.
Cost-Sharing and Assistance
Each county is authorized to maintain a Noxious Weed Control Fund to pay for enforcement and control activities.3Illinois General Assembly. Illinois Code 505 ILCS 100/15 County authorities administer these funds and can share the cost of managing new infestations, so the full bill does not always land on the landowner when you engage the county early.
The University of Illinois Extension maintains identification guides and regulatory summaries for both noxious and exotic weeds, and the Department of Agriculture provides technical guidance on approved control methods.10Illinois Extension. Illinois Regulations Regarding Invasive Plant Species
At the federal level, the USDA’s Environmental Quality Incentives Program (EQIP) offers financial and technical assistance to agricultural producers and forest landowners addressing natural resource concerns on working lands, including invasive species management. Applications are accepted on a rolling basis, with ranking dates set by each state.11Natural Resources Conservation Service. Environmental Quality Incentives Program If you’re managing a farm or timberland with significant infestation, contact your local NRCS office before committing to an expensive control plan on your own.