Native thistles are wildflowers within the genus Cirsium. They occur in a broad range of habitats—pastures, grasslands, prairie remnants, roadsides, idle fields, open woodlands, savannas and wetlands—where they play a vital role in ecosystems. Native thistles provide multiple benefits to pollinators and other wildlife.
Xerces Society staff advocated to remove native thistles as noxious weeds for control in the state of Iowa in December of 2018. In early 2019, native thistles were officially no longer considered Class B noxious weeds for control under the Chapter 58 Noxious Weeds amendment, relieving landowners and land managers of the requirement to control native thistles on their property. This is a milestone for the conservation of biodiversity in the state of Iowa. This brochure describes native and non-native thistles and provides guidance on recognizing the different species and their distinct features.
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