Vindicator Logo

Hogweed sightings often false

Thursday, July 19, 2018

Q. Is hogweed growing in Mahoning County? In Youngstown?

Wendy from Youngstown

A. No, not that we know of, at least! There have been many confirmed sightings in Ashtabula County, though.

Giant hogweed (Heracleum mantegazzianum) became headline news a few years back because of the plant’s sap. A recent finding in Virginia has made people more aware of this plant.

The reason for concern is the effects of the sap of this plant. When a person comes in contact with the sap, it causes the skin to be “highly sensitive to ultraviolet light.” This causes the person’s skin to swell and blister.

At this point, we have had many calls about this plant, and sightings across Mahoning County. None of the plants have ended up being giant hogweed, yet.

Hogweed can be identified by its very large size, up to 15 feet tall with leaves up to 5 feet across. It is in the carrot (parsley) family, thus looking similar to many native plants. The leaves are different shapes and sizes during its life cycle. The large flowers at the top of the plant and purple blotches on the stem are common identification features.

Look-alike plants and plants we have had reported as giant hogweed include:

Wild carrot: Commonly known as Queen Anne’s Lace, this common roadside flower is only about 4 feet tall, has feathery leaves, and many white flowers that are about 4 inches wide.

Poison hemlock: This invasive plant is relatively new to most, invading the area along roadsides and railroad tracks. It is quite established all over Mahoning County and Ohio. It can get 10 feet tall, but the leaves are more fern-like. The flowers look like larger versions of wild carrot. This plant contains highly poisonous alkaloids that can be fatal.

Cow parsnip: This is the plant that is most similar to hogweed, but it only gets about 8 feet tall. The leaves are also compound leaves, but are divided into three distinct segments.

Elderberry: Because of its height and white blooms, this plant is being reported more and more as hogweed. This native shrub is quite large, up to 16 feet tall, and has large leaves around 7 inches wide and long. It has white, umbel flowers that can be 10 inches wide. Elderberry plants spread by suckers, making them appear in large clumps along roadsides and in fence rows. Observing berries on these plants in a few weeks instead of seeds will help avoid confusion.

Visit for photos of hogweed to help you with identification of a possible sighting.

Eric Barrett is OSU Extension educator for agriculture and natural resources in Mahoning County. Call the office plant and pest clinic at 330-533-5538 to submit your questions. Regular clinic hours are 9 a,m, to noon Mondays and Thursdays.