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Bureau of Farm Products and Plant Industries
Pest Alert
Giant Hogweed
NEW!!! Media Advisory
Poisonous Plants Media Outreach & Education Page.
updated December 2006
This invasive plant is native to central Asia. Its sap can cause severe skin irritation and blindness. Wear protective clothing and eyewear when removing.
Common name: |
Giant Hogweed |
Scientific name: |
Heracleum mantegazzianum |
Confirmed Massachusetts sites.
[Note: Control status is noted for known giant hogweed stands within each
town].
|
Andover
(eradicated) |
Blandford
(control efforts in progress) |
Boston
(near eradiaction) |
Gill
(control efforts in progress) |
Granville
(control efforts in progress) |
Groton
(near eradication) |
New Marlboro
(control efforts in progress) |
North
Brookfield
(near eradication) |
Sandwich
(eradicated) |
Southwick(control efforts in progress) |
Sutton
(control efforts in progress) |
Turners Falls
(control efforts in progress) |
Wakefield
(eradicated) |
Westfield
(control efforts in progress) |
West Springfield
(control efforts in progress) |
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Other states: |
Established in New York, Pennsylvania, Oregon and Washington State.
Reported in Maine, Michigan, and Washington DC.
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Impact: |
Hogweed is a public health hazard. Its clear, watery sap has toxins that cause
photo-dermatitis. Skin contact followed by exposure to sunlight produces
painful, burning blisters that may develop into purplish or blackened
scars. Contact with the eyes can cause temporary or permanent blindness. |
Description: |
A biennial or perennial herb growing 8 to 15 feet tall, giant hogweed usually has a taproot or occasionally fibrous root. The hollow stems are 2 to 4 inches in diameter with dark reddish-purple splotches and coarse white hairs.
The deeply incised compound leaves grow up to 5 feet in width. Hairs on the underside of the leaf are stiff, dense and stubby.
The large umbrella-shaped flower heads are up to 2 1/2 feet in diameter
across a flat top with numerous small flowers produced in mid-May through
July.
Some plants die after flowering; others flower for several years. The plant
produces flattened, 3/8 inch long, oval dry fruits that have a broadly
rounded base and broad marginal ridges. Plants sprout in the early spring
(or late winter in mild years) from the roots or from seed.
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Similar species commonly confused with Giant Hogweed: |
Cow parsnip (Heracleum maximum), Angelica (Angelica atropurpurea), Wild chervil (Anthriscus sylvestris), Poison Hemlock (Conium maculatum), Queen Anne's Lace (Daucus carota), Golden Alexanders (Zizia aurea).
Click here for a comparison of giant hogweed and similar species.
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Control methods: |
Call the MDAR Division of Regulatory Services at 617-626-1779 for guidance on controlling this pest. |
![](https://webarchive.library.unt.edu/eot2008/20090116073646im_/http://www.mass.gov/agr/images/invspcr.gif) |
Have you seen this weed?
![giant hogweed towers over six-foot tall man](giant_hogweed_granville_small.jpg)
(Click to view a larger image.)
IDENTIFY Giant Hogweed
REPORT Giant Hogweedby filling out this on-line form
or call the Hogweed Hotline at 617-626-1779
More giant hogweed information...
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