Spotted & Diffuse Knapweed
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Spotted Knapweed Life Span: Biennial (or short-lived perennial) |
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Diffuse Knapweed Life Span: Biennial (or short-lived perennial) |
The reason these plants are considered noxious is:
- They are very aggressive, infesting dry rangeland and waste areas
- They are prolific seed producers
- They are highly competitive, even killing vegetation that grows below them
These two plants have been on the noxious weed list since 1992. They have yet to be located in Douglas County. Both plants are very difficult to distinguish between each other in the rosette stage. Both plants behave and look almost alike, but they have different blossom bracts (under the flower), and the Spotted is usually purple, while the Diffuse is usually white.
Control Method
For a more detailed description of Knapweeds, check out the Nebraska Weed Control Association Website. For more information on Knapweeds in Douglas County, please call 444-4583 or email our office.


