A poisonous weed with sap that can cause third-degree burns and vision impairment is dangerously close to East Tennessee.
Virginia Tech researchers identified giant hogweed in Clarke County, Virginia, last week, but have confirmed that the plant has not naturalized to the environment. Officials are working with the land owner to eradicate it.
“There have not been any reported or confirmed sightings in East Tennessee,” said Diane Warwick, Urban Watershed Forester for the Tennessee Department of Agriculture and Forestry. “The plant has been reported in Watauga County, North Carolina.”
During the summertime in East Tennessee, over-vegetation is abundant due to lack of mowing and the perfect climate for weeds to thrive. Vacant lots, roadside ditches or open-spaced areas between residential areas should be alarming to the public, because the giant hogweed could be growing in the East Tennessee region without anyone even knowing, according to a U.S. Department of Agriculture fact sheet.
The plant has an umbrella-shaped bundle of white flowers and can grow up to 20 feet tall. It is commonly mistaken for the cow parsnip, a weed that grows abundantly in all of the aforementioned spaces in the region, but rarely exceeds 6 feet in length.
According to a joint report by The Bugwood Network, USDA Forest Services, USDA Animal and Plant Health Inspection Service and University of Georgia, the giant hogweed plant has a hollow stem that grows 2 to 4 inches in diameter with dark maroon spots and bristles. The leaves can grow up to 5 feet in width and the flower-heads can grow about 2.5 feet in diameter.
The giant hogweed flowers grow from around mid-May until July. The plant also produces flat, oval-shaped fruit with a broad base and long ridges, according to reports.
The plant is extremely dangerous when the clear, watery sap comes into contact with the skin.
“It can cause painful blisters and phytophotodermatitis,” said Warwick. “This makes the skin extremely sensitive to sunlight for years after exposure.”
EDDmaps.org is a tool that government agencies use to map out the spread of the weed. The source also lists helpful information about the invasive species, including the ecological threat that the plant can have on the environment in which it grows. Giant hogweed could cause increased soil erosion, experts say.
According to Ontario’s Invading Species Awareness Program, the giant hogweed seeds could take years to germinate. However, the seeds remain viable in the soil for up to 15 years. Once the plant produces seeds, it dies.
It is reported that each plant could produce roughly 50,000 seeds. Seeds dropped in streams can float up to three days and can be spread about 10 meters by wind.
Hogweed has been reported all along the Northeast and Mid-Atlantic regions, with the closest sighting being in Western North Carolina.
The number one rule when discovering this weed, according to multiple experts and government agencies, is to not touch the plant.
The Pennsylvania Department of Agriculture reported that mowing or “weed-wacking,” is highly discouraged, as the sap could easily spill from the plant and cause tremendous harm by making contact with the skin or eyes. It is recommended to use pre- and post-emergent pesticides.
“I would recommend having a specialist of some kind come to look at the site before treating — a Tennessee Invasive Plant Council member, area forester, agriculture plant regulator or somebody from the UT Extension,” said Warwick. “Since this can be a toxic plant, we do not recommend taking samples, but rather contacting an expert.” Property owners who think they spot the weed should steer clear and report the sighting to the UT Agriculture extension office in Knoxville by calling 865-974-7114.