Content adapted with permission from the Indiana Department of Natural Resources, a partner in the Natural Heritage of Indiana project. More information can be found here.

Invasive plant species are a threat to natural areas in Indiana. They displace native plants, eliminate food and cover for wildlife, and threaten rare plant and animal species. However, among natural resource professionals there is little consensus on which species constitute the greatest threat to natural areas. Consequently, species that are considered a grave threat by some resource professionals are still recommended by other resource professionals and sold by nurseries.

Some definitions according to Indiana Codes

"DETRIMENTAL PLANTS" ( IC 15-3-4-1 ) = Includes all noxious weeds, "and, in residential areas only, noxious weeds and rank vegetation. The term does not include agricultural crops."

"EXOTIC PLANT" = Plants that are "not native" to the area under consideration.

"EXOTIC WEED" ( IC 14-8-2-87.5 ) = a weed that is not native to Indiana.

"INVASIVE PLANT" = Plants, native or exotic, with an exceptional ability to establish and to take over existing vegetation.

"NOXIOUS WEEDS" ( IC 15-3-4.6-2 ) = (1) Canada thistle (Cirsium arvense). (2) Johnson grass and Sorghum almum (Sorghum halepense).
(3) Bur cucumber (Sicyos angulatus). (4) Shattercane ( Sorghum bicolor (L.) Moench spp. drummondii (Steud.) deWet).

"WEED" ( IC 14-8-2-316 ) = Any plant that is competitive, persistent, pernicious, and interferes with human activity, and as a result is undesirable.

Some examples of plants managed by law in Indiana are

• BRAZILIAN ELODEA
• PURPLE LOOSESTRIFE ( IC 14-2412-7 )
• MULTIFLORA ROSE ( IC 14-24-12-5 )
• JOHNSON GRASS ( IC 15-3-5-1 )
• MARIJUANA ( IC 15-3-4.6-1 )
• CANADA THISTLE
• BUR CUCUMBER
• SHATTERCANE
• SORGHUM ALMUM

Indiana DNR's site has more information on specific invasive species and forms to report a sighting. More»