The Minnesota Department of Agriculture (MDA) has added six new weeds to the state’s noxious weed list. The noxious weed list places weeds into four categories – prohibited eradicate, prohibited control, restricted and specially regulated and defines how the weeds must be controlled.

Three weeds on the list also changed categories.

As the lead agency for noxious weed regulation, the MDA, with recommendations from the noxious weed advisory committee, updates the state’s noxious weed list every three years.

Plants are placed on a list because they may be harmful to public health, the environment, public roads, crops, livestock or other property. There are restrictions on the weed’s sale, transport, growth or spread.

The new species added to the list are:

• Japanese honeysuckle (Lonicera japonica) as prohibited eradicate

• Bohemian knotweed (Polygonum x bohemicum) as prohibited control  

• Siberian peashrub (Caragana arborescens) as restricted (exemption for Green Spires® Caragana - Caragana 'Jefarb')

• European alder (Alnus glutinosa) as restricted

• Norway maple (Acer pltanoides) as specially regulated

• Winged burning bush (Euonymus alatus) as specially regulated

The three species that changed categories are:

• Japanese knotweed (Polygonum cuspidatum) and giant knotweed (P. sachalinense) were moved from specially regulated to prohibited control.

• Tree of Heaven (Ailanthus altissima) was moved from restricted to prohibited eradicate.

Prohibited eradicate species are considered a serious threat and are the state’s highest priority noxious weeds.

These species must have all above- and below-ground parts of the plant destroyed. Prohibited control weeds are found in higher populations than those on the eradicate species list, and they must be stopped before the weeds mature and spread through seeds, cuttings and other plant parts.

Restricted noxious weeds are widely found throughout Minnesota.

Landowners who have restricted weeds on their property are encouraged to manage these species but cannot be forced to do so under the noxious weed law.

Specially regulated plants are native or have the potential to cause harm in non-managed landscapes. These weeds have specific management plans developed by the MDA, and measures must be taken to minimize their potential harm.

To view the updated noxious weed list and to learn more about the category definitions, visit the MDA Web site at www.mda.state.mn.us.

- Photo courtesy of the Minnesota Department of Agriculture