Issue 8, June 15, 2015

Regulated Weeds

The State of Illinois has two "legal" lists of problematic plants that require attention – Noxious Weeds and Exotic Plants.

Noxious Weeds

The Illinois Noxious Weed Law, set into Illinois Administrative Code, lists 10 weeds that must be controlled on property owned or managed.  These weeds have detrimental effects on public health, agricultural crop production, or animal production.  This law is under the direction of the Director of the IL Department of Agriculture.  Most counties in Illinois have a designated Weed Commissioner for local control authority.

Weeds on this list include Common Ragweed (Ambrosia artemisiifolia), Giant Ragweed (Ambrosia trifida), Marijuana (Cannabis sativa), Musk Thistle (Carduus nutans), Canada Thistle (Cirsium arvense), Kudzu (Pueraria montana, P. lobata), Perennial Sowthistle (Sonchus arvensis), and various sorghums including Johnsongrass (Sorghum halepense) and Columbus grass (Sorghum almum).

The two ragweeds need only be controlled within the corporate limits of cities, towns and municipalities.  All other weeds on the list must be controlled anywhere in Illinois.

Noxious weeds must be controlled so they don't produce seeds or any other means for propagating, or totally eradicated using legal means.

It should be noted these are outdoor-grown weeds.  That's important now with one of the weeds.

More information on the IL Noxious Weed Law can be found at:

Exotic Weed Act

The Illinois Exotic Weed Act, also set into Illinois Administrative Code, is managed by the IL Department of Natural Resources.  These non-native plants, when planted, will spread by seeds or vegetative propagules (rhizomes, bulbs, tubers, corms, etc.) and naturalize, degrading natural communities, reduce the value of fish or wildlife habitat, or threaten an Illinois endangered or threatened species.

For most of these plants, it's the seeds that have caused these plants to spread, particularly in forested and wooded areas.

This law doesn't require the owner or manager of property to remove these plants like the IL Noxious Weeds.  However, do everything to prevent them from spreading, including removing flowers before they set seed.  The Act does state you cannot sell or plant these without permission from IDNR. 

The following species are on the list.  Additionally, and this is crucial, all their cultivars are included, no matter who or what says the cultivars are sterile.  Any cultivar of these plants CANNOT be legally sold or planted in Illinois without a permit from IDNR.  This includes all the so-called sterile purple loosestrife cultivars as well as the Fine-Line® buckthorns.

Included plants include Japanese honeysuckle (Lonicera japonica), multiflora rose (Rosa multiflora), purple loosestrife (Lythrum salicaria), common buckthorn (Rhamnus cathartica), glossy buckthorn (Rhamnus frangula), saw-toothed buckthorn (Rhamnus arguta), dahurian buckthorn (Rhamnus davurica), Japanese buckthorn (Rhamnus japonica), Chinese buckthorn (Rhamnus utilis), and kudzu (Pueraria lobata).  Kudzu is the only plant on both lists.

At the moment, IL Senate Bill 681 seeks to amend the Exotic Weed act, adding bush honeysuckles (Lonicera maackii, Lonicera tatarica, Lonicera morrowii, and Lonicera fragrantissima), exotic olives (Elaeagnus umbellata, Elaeagnus pungens, Elaeagnus angustifolia), salt cedar (all members of the Tamarix genus), poison hemlock (Conium maculatum), giant hogweed (Heracleum mantegazzianum), Oriental bittersweet (Celastrus orbiculatus), and lesser celandine (Ficaria verna), teasel (all members of the Dipsacus genus), and Japanese, giant, and Bohemian knotweed (Fallopia japonica, syn. Polygonum cuspidatum; Fallopia sachalinensis; and Fallopia x bohemica, resp.) as designated exotic weeds.

Interestingly, some of the above are obvious weeds (poison hemlock, giant hogweed, teasels) but are sold for various unsubstantiated herbal or medicinal uses on the internet.

It should be stressed that these plants are NOT currently illegal to plant or sell in Illinois.  Ultimately, it depends on what the Illinois legislature and governor does in the next month. On the other hand, we know the proposed plants are terribly invasive; a wise gardener/landscaper would remove these plants from their design palette, and seriously consider removing these and the designated exotics from the landscape.

For more information, refer to: (David Robson)

David Robson

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