Diffuse knapweed is a non-native noxious & invasive species that originates from southern Europe, Asia, and north-central Ukraine. It was introduced to North America accidentally in the 1890s. It is a highly aggressive, short-lived, non-creeping perennial or annual that reproduces from seeds only.
Diffuse knapweed plants break off at the soil surface and become tumbleweeds over winter so they can disperse their seeds. It reduces agricultural yields and forage values. It also crowds out native species, negatively impacting the wildlife that depend on them.