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Virginia Tech News / Articles / 2018 / June 

No evidence giant hogweed spreading widely despite additional sites in state

June 25, 2018

image of Jordan Metzgar of the Massey Herbarium at Virginia Tech
Jordan Metzgar, curator of the Massey Herbarium at Virginia Tech, has identified plants as the giant hogweed. (Photo Massey Herbarium, Virginia Tech)

While the presence of giant hogweed has been confirmed in multiple Virginia locations, experts at Virginia Tech and Virginia Department of Agriculture and Consumer Services (VDACS) say there is no evidence the dangerous weed with toxic sap is spreading widely.

Virginia Tech plant experts, working with VDACS officials and Virginia Cooperative Extension, have confirmed the plant growing in Clarke County, Rockingham County, and Fauquier County based on submitted plant specimens. Virginia Tech experts have confirmed an additional site in Alexandria based on photographs.

“There’s not cause for widespread worry. It’s growing where it’s been planted from what we’ve seen.  We see little evidence of it widely spreading,” said Virginia Tech’s Michael Flessner, an assistant professor and Extension weed science specialist who has worked closely with Jordan Metzgar, curator of the Massey Herbarium at Virginia Tech, to identify that the plants are indeed giant hogweed.

Initial management measures have been taken at all four sites, and VDACS will be following up with subsequent site visits.

Giant hogweed is a Tier 1 noxious weed on VDACS’ Noxious Weed List. A Tier 1 classification means the weed was previously unknown in the commonwealth. The Department of Conservation and Recreation lists giant hogweed as an early detection invasive plant, which means it is not established in Virginia and, if found, the goal is to eradicate it before it becomes established. 

When exposed to skin, the sap from a giant hogweed plant can cause severe skin and eye irritation, painful blistering, and potentially permanent scarring. The plant is easily confused with other look alike plants such as cow parsnip, elderberry, and others. People who think they have found giant hogweed should take a digital photo of the leaf, stem and flower, being careful to avoid skin contact with the plant. They can report it to the local office of Virginia Cooperative Extension or file an online report here.

Giant hogweed is a very distinct plant when set against Virginia landscapes and although it has some similar characteristics as cow parsnip, angelica, and Queen Anne’s lace, its size sets it apart. It can grow up to 15 feet tall with leaves as large as five feet across but most plants identified in Virginia have been 5 to 10 feet tall, with largest leaves approximately 2 feet across. The white flower cluster contains 50–150 flower rays spreading up to 2 feet across. Giant hogweed also has purple splotches and coarse, sparse white hairs on the stem. The leaf is more incised and angular than cow parsnip, which is giant hogweed's closest look alike. 

Anyone who suspects they have found giant hogweed should take photos, check online to compare the plant to photos, and then contact a Virginia Cooperative Extension agent or file an online report here. Information is available here to learn more about invasive species in Virginia and the ways to prevent spread. People also may contact the VDACS Office of Plant Industry Services at 804-786-3515

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