UConn and the Connecticut Invasive Plant Working Group (CIPWG) are asking state residents to be on the lookout for Giant Hogweed, which typically blooms during July. Giant Hogweed (Heracleum mantegazzianum) is an invasive, non-native plant from Eurasia that was first identified in Connecticut in 2001. This Federal Noxious weed was confirmed in 25 towns in all 8 counties in surveys conducted several years ago, but many of the populations are now under control. The most recent confirmed locations of Giant Hogweed were found in 2011. Numerous reports of suspect giant hogweed plants blooming in Connecticut have recently been received, but to date all of the 2018 reports have been negative. Several plants are sometimes mistaken for giant hogweed, such as the native cow parsnip, which is related to Giant Hogweed but blooms earlier in June.
Giant Hogweed is a biennial or perennial herbaceous plant that can grow up to 15 feet tall with leaves 5 feet long. The hollow stems of the plant are 2 to 4 inches in diameter. The sap of Giant Hogweed may cause skin to be more sensitive to sunlight and produce painful blisters. Large numbers of small white flowers are borne on umbel-shaped inflorescences that can grow to 2.5 feet across. Giant Hogweed seeds are elliptical in shape, and cow parsnip seeds are heart-shaped on one end (this is the most definitive way to identify the two species). Mature Giant Hogweed seeds can survive in the soil for up to seven years and can float on water for several days, further spreading the plants to new areas. Giant Hogweed has invaded natural areas such as riverbanks and woodland edges, where it displaces native plants and upsets the ecological balance of these important habitats, and it has been accidentally introduced into managed landscapes.
UConn and the Connecticut Invasive Plant Working Group (CIPWG) are conducting educational outreach to alert the public about Giant Hogweed and its serious health hazards. The CIPWG website (https://cipwg.uconn.edu/giant-hogweed-in-connecticut/) has information on Giant Hogweed with plant descriptions, photos, control options, and an online reporting form.
To report a Giant Hogweed sighting, we recommend that you first visit the CIPWG website and compare your suspect plant with the photos and descriptions provided. You can then report the plant online via the CIPWG website (click on the link “Report Hogweed Sighting”) or contact Donna Ellis at UConn (email firstname.lastname@example.org; phone 860-486-6448). To control Giant Hogweed, follow control recommendations on the CIPWG website. Always wear protective clothing while handling the plants.