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Washington State Noxious Weed Control Board |
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Class A Noxious Weed
Giant Hogweed
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Plant family:
Apiaceae (Umbelliferae)
Year listed:
Native to: The
Caucasus mountains and southwestern Asia.
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Why is it a noxious weed? |
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Giant hogweed forms dense canopies, outcompeting
native species and increases soil erosion along streambanks. It is a
public hazard, the plant exudes a clear watery sap which sensitizes the
skin to ultraviolet radiation. This can result in severe burns to the
affected area causing blistering and painful dermatitis. Giant hogweed
is also Federally listed as a noxious weed.
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How would I identify it? |
| General Description:
Giant hogweed is a member of the parsley or
carrot family, it is distinguished by it's large size, growing to a
height of 15-20 feet.
Leaves:
Flowers:
Stems:
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How does it reproduce? |
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Reproduction is through seed and perennating buds formed on the
crown and tuberous root stalk.
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Where does it grow? |
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Most common along roadsides, other rights-of-way, vacant lots, streams and rivers. |
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What is the distribution in Washington State? |
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How do I control it? |
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General control methods: Always wear protective clothing and avoid getting sap on skin, the sap that causes the burning is contained in all portions of the plant. Cultural: Plants may be dug-out but care should be taken to remove much of the root stalk this can be difficult. Herbicide: Please refer to the PNW Weed Management Handbook, or contact your county noxious weed coordinator. Mechanical: Mowing serves only to stimulate budding on the perennating root stalk, but might be successfull if done consistently and persistently enough to starve the rootstalk. Biological: Cattle and pigs are cited as possible biocontrol agents. Both eat giant hogweed without apparent harm. |
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Are there plants that may be confused with Giant Hogweed? |
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Cow Parsnip Heracleum lanatum, is a native plant in
Washington and except for it's size, has a similar appearance to
Giant Hogweed. A field guide of Pacific Northwest wildflowers can
help you with identification, or you can contact the
WA Native Plant Society. Your
county noxious weed coordinator can also help with
identification. Click on photos below to enlarge. |
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For more information |
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For more information, download our
Written Findings.
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Last updated July 09, 2008