Musk Thistle
Carduus nutans
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Family: AsteraceaeOther common names: nodding thistle Weed Class: B Year Listed: 1988 Native to: Europe and Asia Toxic: not known to be
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Why is it a noxious weed? |
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It invades pastures and fields, crowding out desirable forage plants. Livestock will not graze in areas heavily infested with must thistle, thus decreasing available pasture. It hinders stream bank access, and is problematic in grain fields. |
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How would I identify it? |
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General Description: Musk thistle is typically a biennial though may be a winter annual. It can grow up to 7 feet tall. Flower Description: Flowerheads mostly solitary and large, up to 3.1 inches across and nodding. Bracts under flowerheads are broad, some reflexed with a spiny tip. Each plant can have 50 to 100 flower heads. Leaf Description: Leaves are alternate, deeply lobed, spiny and may have some hairs on the underside leaf veins. Stem Description: Stems have spiny wings. Fruit/Seed Description: Seeds (achenes) are smooth and hairless. May be confused with: |
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How does it reproduce? |
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Musk thistle reproduces by seed. |
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Where does it grow? |
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Musk thistle grows in pastures, rangeland, native meadows, roadsides, forests, stream banks, and occasionally grain fields. Please click here to see a county level distribution map of musk thistle in Washington. |
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How do I control it? |
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General Control StrategyEstablishing a dense, well-maintained pasture is effective in preventing a musk thistle infestation.
Mechanical ControlMusk thistle can be dug or grubbed out. Cultural ControlCultivation in cropland will kill young musk thistle seedlings. Biological ControlA seed eating weevil, Rhinocyllus conicus, is quite effective in reducing seed output.
Herbicide ControlPlease refer to the PNW Weed Management Handbook, or contact your county noxious weed coordinator. |
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For more information |
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Additional Photos |
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