Download Giant Hogweed (Heracleum mantegazzianum)

Giant Hogweed (Heracleum
mantegazzianum)
Life history, control and monitoring
efforts.
By: The Nature Conservancy
Life History
• Habitat
• Ravines, roadsides, ditches and riparian areas.
• Residential properties and vacant lots.
• Wooded or open space areas between residential
communities.
Morphology
• Height: 8 – 15ft when in flower
• Leaves: large, compound,
deeply incised, and 3 – 5ft
wide. Hairs on the underside
are stiff, dense, and stubby but
only about .25mm long.
• Petioles have short course
white hairs at the base.
• Flower head: Flat topped, up to
2.5ft across.
• Seeds mature in August,
distributed summer/fall (water,
wind, mowers)
Similar species
• Picture!
Cow Parsnip
Angelica
Cow Parsnip
Safety
• Extreme skin hazard!
• Eye exposure can lead to temporary or
permanent loss of vision.
• If exposure does occur wash skin with
soap and water, avoid the sun, and seek
medical attention.
• When working with plants cover all parts of
the body.
Control
• Difficult to control due to phototoxicity. (ie. Contact with
plants sap and exposure to UV
light will cause severe
blistering)
• Hand-digging
• Repeated mowing, weakens
plant but large roots will
remain alive for years.
• Herbicide sprays, a foliar
treatment of glyphosate or
triclopyr. (Has been effective
in the Pacific Northwest).
Monitoring
Giant Hogweed Locations in Town of Lewis
!
Stinebecker Rd
47
!
!
Mathis Rd
!
Mud Lake Rd
!
West Leyden
!
Legend
!
.
Giant Hogweed
lewis
publiclands
Towns
0
550 1,100
2,200
3,300
4,400
Meters
Other sightings?