CLARKE COUNTY, VIRGINIA — Virginians are being warned to keep their eyes out for the giant hogweed plant, which can cause third-degree burns and even blindness.

Thirty of the deadly plants were recently found at a site in Clarke County, according to the Massey Herbarium at Virginia Tech, though they've been known to grow in other states.

Giant hogweeds are huge and invasive. They grow up to 14 feet and have sharply lobed leaves, umbrella-shaped white flowers, and hollow, hairy, purple-splotched stems, according to the New York Department of Environmental Conservation.

Their sap contains toxins called furanocoumarins, which can make human skin hypersensitive to sunlight.

If not washed and covered immediately, the skin can develop itchy burning blisters, with scarring, discoloration, and sometimes persistent sun sensitivity that can last years. The sap has also been known to cause temporary or permanent blindness when it comes in contact with the eyes.

Experts strongly advise against taking out the plant with a weed whacker, since the sap could splatter and spread.

Physical removal or the use of herbicides is a much more effective — not to mention safer — option. Or, just call it in and leave it to the pros.