Invasive in Pennsylvania

Giant Hogweed

Heracleum mantegazzianum

Description: Biology and Spread:

Giant hogweed is an Over 100,000 seeds are incredibly tall biennial or produced annually by each perennial herb, growing up to . These seeds can be 20 feet in height. Its stout spread by animals, surface stems are hollow with purple runoff of rain, or by wind. splotches and course bristles. Prolific seed production, Deeply incised compound combined with a rapid growth leaves with stiff hairs can rate, results in dense colonies. Terry English, USDA APHIS PPQ grow up to five feet in width. www.forestryimages.org The large umbrella-shaped Ecological Threat: flower heads have numerous Background: small white flowers, which Because of its size and rapid develop into flattened, oval- growth, giant hogweed is an Giant hogweed, an enormous shaped fruit. aggressive competitor capable member of the carrot family of displacing native plants. It , was brought to the dies back during the winter as an months, leaving bare ground ornamental and as a source for open to erosion on riverbanks the anise-scented spice golpar, and steep slopes. The sap of which is used in Iranian giant hogweed makes human cooking. It is now designated skin sensitive to ultraviolet as a federal noxious weed. light, resulting in severe burns and blisters. Contact with the eyes can cause permanent Range: blindness.

This plant is native to central and southwest Asia, but has Robert Vidéki, Doronicum Kft. been introduced into Europe www.forestryimages.org and . In the United States, it can be found Habitat: primarily in the Northeast, Great Lakes and Northwest Giant hogweed can be found regions. along railroads, roadsides, rights-of-ways, vacant lots,

streams, rivers, waste areas and fallow fields, particularly Donna R. Ellis, University of Connecticut in disturbed soils. www.forestryimages.org

How to Control this Species: If You See This Plant:

Giant hogweed is on the Physical Chemical Pennsylvania Noxious Weed Individual plants can be dug Foliar treatments with Control List. It is illegal to sell, up, making sure to remove glyphosate or triclopyr have plant or transport this species. the entire root system. been effective. Glyphosate is If you believe that you have considered the best choice, found a new population of this Repeated mowing or cutting and should be applied in plant, please contact Melissa can eventually starve the spring or early summer when Bravo, PA Dept. of plant of energy. This plants are actively growing. A Agriculture, at 717-787-7204. practice needs to be follow-up application in performed numerous times mid-summer may be during a growing season. necessary. Glyphosate is nonselective and may kill Extreme care should be taken desirable plants, including when undertaking these grasses. methods. Protective clothing and eye protection are a good Biocontrol idea. Cattle and pigs are apparently

not affected by the sap and eat www.forestryimages.org

giant hogweed without harm. Doronicum Kft. Robert Vidéki, Look-A-Likes:

Some of our larger native References: members of the carrot family, such as cow Sea Grant: http://www.dec.ny.gov/docs/ (Heracleum maximum) and lands_forests_pdf/ghfactnyseagrant.pdf purple-stemmed (Angelica atropurpurea), may be St. Lawrence-Eastern Lake Ontario PRISM of New York State: confused with giant hogweed. http://www.sleloinvasives.org/about-invasives/target-species/ giant-hogweed/ Cow Parsnip USDA Forest Service: http://www.na.fs.fed.us/fhp/ invasive_plants/weeds/giant-hogweed.pdf

For More Information:

DCNR Invasive Species Site: http://www.dcnr.state.pa.us/

William M. Ciesla, Forest Health Mgmt. Intl. conservationscience/invasivespecies/index.htm www.forestryimages.org